The group of extinct Cretaceous reptiles known as the Mosasaurs or
Pythonomorpha was defined by Cope, “to whom Science is so largely
indebted for its present knowledge of this interesting order of
reptiles” (Marsh), in 1869.[4] Although some of the characters assigned
by him to the order have since been shown to be inapplicable, and
the group to have less value, yet his name, Pythonomorpha, has been
generally retained. Lydekker and Zittel have assigned to the group a
subordinal value, as has also Marsh, though under a different name.
Owen rejected it entirely, and Baur, more recently,[5] has united it
with the Varanidae to form a super-family, as follows:
Suborder Platynota.
Super-family Varanoidea.
Families Mosasauridae, Varanidae.
Super-family Helodermatoidea.
Family Helodermatidae.
The group, whatever may be its rank or position, includes, so far, the
following genera: _Mosasaurus_ Conyb., _Liodon_ Owen, _Platecarpus_
Cope, _Clidastes_ Cope, _Baptosaurus_ Marsh, _Sironectes_ Cope,
_Plioplatecarpus_ Dollo and _Hainosaurus_ Dollo. _Pterycollasaurus_
Dollo, founded upon _Mosasaurus maximilianus_ Goldf., is omitted
as doubtful. All of these genera, save _Plioplatecarpus_ and
_Hainosaurus_, have been recorded from North America, _Clidastes_,
_Baptosaurus_ and _Sironectes_ being peculiar to this country. Of these
latter three genera, however, _Clidastes_ alone is well known; but this
genus is suspected by Lydekker of being the same as the imperfectly
known European _Geosaurus_ Cuvier. Thus it seems that the genera, or
at least the most of them, have a wide distribution; _Platecarpus_, in
fact, is said to occur in New Zealand.
[4] Proc. Bost. Soc. Nat. Hist., p. 253.
[5] Science, xvi, p. 262, Nov. 7, 1890.
In America, members of the group have been discovered in the Cretaceous
deposits of New Jersey, Alabama, North Carolina, the upper Missouri
region, Nebraska, Kansas and New Mexico. Probably nineteen-twentieths
of all the known specimens, however, have been obtained in western
Kansas. The material now in the University Museum, all from Kansas,
comprises several hundred specimens of these animals, including,
probably, the best ones known. It is upon this material that the
following preliminary studies are chiefly based.
The genus _Clidastes_, as first described by Cope, was based upon
two dorsal vertebrae of _C. iguanavus_, the type species, from New
Jersey. Shortly afterward, however, he gave a full and careful generic
description, as derived from an unusually good specimen of an allied
species, _C. propython_, from Alabama. Only a little later, Marsh
described a genus, which he called _Edestosaurus_, from Kansas, but
without giving any real, distinctive differences from _Clidastes_,
following the very reprehensible practice of naming supposed new forms
in the hopes that future distinctive characters might be found. The
genus _Edestosaurus_ has been rejected by nearly all save the authors
of the American text-books in Geology. It seems hardly necessary to
point out the identity. The only distinctive character the author
gave for his genus was the insertion of the pterygoid teeth, and even
this character he modified later—“Palatine (sic) teeth more or less
pleurodont.”[6]
[6] Amer. Journ. Sci. iii, June 1872.
This character, even were it real, is of very slight value; indeed it
cannot be used to distinguish the species even.
_Clidastes_ is, without doubt, one of the most highly specialized
genera in the group, and, what is very interesting, is one of the
latest. It occurs in Kansas in the uppermost part of the Niobrara beds,
in the horizon so markedly characterized by the toothed birds. Both
_Platecarpus_ and _Liodon_ occur, though in diminished numbers, almost
to the very lowest portion, but _Clidastes_ has never been found except
towards the top. From measurements made the past season, the thickness
of the beds in which these saurians occur cannot be less than six
hundred feet.
The following species have been found in Kansas: none of them are known
to occur elsewhere.
MOSASAURIDAE.
_Mosasauridae_ Conybeare, in Cuvier, Ossem. Foss., 2nd ed.,
p. 338, 1824.
_Clidastidae_ Cope, Extinct Batr. Rept. and Aves of N.
Amer., Trans. Amer. Phil. Soc. xiv, p. 50, 1870.
_Edestosauridae_ Marsh, Amer. Journ. Sci. xxi, p. 59, July
1878.
CLIDASTES.
? _Geosaurus_ Cuvier, Ossem. Foss. 2nd ed., 328, 1824,
(_fide_ Lydekker.)
_Clidastes_ Cope, Proc. Acad. Nat. Sci. Phil. 1868, p. 233;
Ext. Batr. etc., p. 21, 1870.
_Edestosaurus_ Marsh, Amer. Journ. Sci. i, p. 417, June,
1871.
=C. cineriarum.=
_Clidastes cineriarum_ Cope, Proc. Amer. Phil. Soc., 1870,
p. 583; Cret. Vert. etc. pp. 137, 266, pl. xxi, ff.
14-17; Bullet. U. S. Geol. Surv. Hayden, iii, p. 583.
=C. dispar.=
_Edestosaurus dispar_ Marsh, op. cit. i, p. 447, June 1871;
iii, pl. xi., June, 1872.
=C. velox.=
_Edestosaurus velox_ Marsh, Amer. Journ. Sci. i.
p. 450, June, 1871.
_Edestosaurus pumilus_ Marsh, ibid. p. 452.
? _Clidastes affinis_ Leidy, Proc. Acad. Nat. Sci., 1870,
p. 4; Rep. U. S. Geol. Surv., Hayden, vol. i, p.
283, 1873.
? _Edestosaurus dispar_ Marsh, op. cit. xix, pl. i, f. 1,
Jan., 1880.
=C. Wymani.=
_Clidastes Wymani_ Marsh, Amer. Journ. Sci. i, p. 451,
June, 1871; iii, p. 202, April, 1872.
_Edestosaurus Wymani_ Marsh, op. cit. iii, p. 464, June,
1872.
=C. tortor.=
_Edestosaurus tortor_ Cope, Proc. Amer. Phil. Soc. Dec.,
1871; Marsh, op. cit. iii, p. 464, June, 1872.
_Clidastes tortor_ Cope, Cret. Vert. Rep. U. S. Geol.
Surv., Hayden, vol. ii, pp. 48, 131, 265, pls. iv, f.
i; xiv, f. i; xvi, ff. 2, 3; xvii, f. 1; xix, ff. 1-10;
xxxvi, f. 3; xxxvii, f. 2; Bullet. U. S. Geol. Surv.
Hayden, vol. iii, p. 583.
=C. stenops.=
_Edestosaurus stenops_ Cope, Proc. Amer. Phil. Soc. p. 330,
1871: Marsh, Amer. Journ. Sci. iii, p. 464, June, 1872.
_Clidastes stenops_ Cope, Cret. Vert. etc. pp. 133, 266,
pls. xiv, ff. 4, 5; xvii, f. 7, 8; xviii, ff. 1-5;
xxxvi, f. 4; xxxvii, f. 3; xxxviii, f. 3.
=C. rex.=
_Edestosaurus rex_ Marsh, op. cit. iii, p. 462, pl. xxii, f. 1, June,
1872.
=C. planifrons.=
_Clidastes planifrons_ Cope, Bullet. U. S. Geol. Surv. No.
2, p. 31, 1874; Cret. Vert. etc. pp. 135, 265, pls.
xxii, xxiii.
=C. Westii.=
_C. Westii_ Williston, n. sp. infra.
CLIDASTES VELOX.
A remarkably complete specimen, referred with considerable certainty
to this species, was obtained by ourselves in western Kansas, (Butte
Creek) in the summer of 1891. A brief preliminary description of the
specimen was given by the senior author in Science, December 8, 1891.
A more complete description is here given, which, it is believed, will
be of service. The specimen is an unusually perfect one, being very
nearly complete, and, as now mounted, shows the bones nearly all in the
position in which they were found. The vertebral column is continuous,
except in one place, where the tail had been bent up over the back; and
complete, save at the very tip of the tail. The skull is complete, or
very nearly complete, and has been restored nearly to the condition in
life. Figures have been made of this portion of the skeleton, and will
be given in a future communication. At present, it may be mentioned
that the lacrymals are small, roughly irregular bones, and pointed at
either extremity. There are no indications of transverse bones, as
there are none in any other skull in the collection.
Cervical vertebrae.
ATLAS. The intercentrum is a small bone with three sides of
nearly equal extent. The two upper, articular surfaces are gently
concave, and meet in a rounded margin; the inferior surface is convex,
both antero-posteriorly and transversely, with a roughened prominence
in the middle. The lateral pieces have indistinctly separated facets
for articulation with the odontoid, the intercentrum and the occipital
condyle. The rather short, flattened lamina extends upward, backward
and inward, approaching, but not reaching its fellow of the opposite
side; it is somewhat dilated distally. Directed outwards and forwards,
there is a stout styliform process.
AXIS. The neural spine of the axis is elongated
antero-posteriorly. It is thin on the anterior portion, but stouter
and longer at the posterior part. The large, stout odontoid process is
united suturally, as is also the well-developed atlantar hypapophysis,
which forms the anterior, inferior portion of the bone. The diapophyses
are the smallest of the costiferous series, with only a small articular
facet for the rib. The ball is strongly and evenly convex, with its
greater diameter transversely. The hypapophysis is the largest of the
series; it is suturally united with the stout, exogenous process of the
centrum, and projects downward and backward; its distal extremity is
roughened for ligamentous attachments.
The third cervical vertebra shows a well-developed zygosphenal
articulation, and stout articular processes. The transverse process is
small, only a little larger than that of the axis, though, unlike that,
it is strengthened by a ridge continued from the anterior zygapophyses.
The hypapophysis is smaller than that of the axis, but, like that,
is directed downward and backward. The spine may be distinguished
from that of any other vertebra by its stout, trihedral shape; it is
directed rather more obliquely backward than in the following vertebrae.
The fourth cervical vertebra differs from the third in having stouter
transverse processes; in the hypapophysis being directed more nearly
downward, and in its smaller size; and in the spine being flattened
antero-posteriorly toward the base.
The fifth cervical vertebra differs from the fourth in the broader
spine, in the stouter transverse processes, and the smaller
hypapophysis.
In the sixth cervical vertebra, the hypapophysis is reduced to a small
ossification, scarcely longer than broad, directed downward. The spine
has reached nearly the full width of those of the following vertebrae,
though somewhat stouter above. The transverse processes are yet stouter.
In the seventh, or last, cervical vertebra the hypapophysis is
wanting, or very rudimentary. The under part of the centrum shows a
rounded ridge or carina, with a slight projection corresponding to the
hypapophysis.
MEASUREMENTS OF THE CERVICAL VERTEBRAE.
1. Antero-posterior diameter of intercentrum of atlas 14 millim.
Transverse diameter of intercentrum 25
Antero-posterior diameter of lateral piece 20
Vertical extent of articular surface 17
Extent of lateral piece 35
Width of lamina above 16
2. Length of axis 43
Transverse diameter of ball 18
Vertical diameter of ball 17
Expanse of transverse processes 28
Elevation of spine above floor of neural canal 34
Antero-posterior extent of spine 50
3. Length of third cervical vertebra 37
Height of spine above floor of neural canal 36
Depth of hypapophysis below floor of neural canal 34
4. Length of fourth cervical vertebra 37
Height of spine above floor of neural canal 39
Depth of hypapophysis below floor of neural canal 35
5. Length of fifth cervical vertebra 37
Height of spine above floor of neural canal 42
Depth of hypapophysis below floor of neural canal 33
Transverse diameter of ball 17
Vertical diameter of ball 18
6. Length of sixth cervical vertebra 37
Height of spine above floor of neural canal 42
Depth of hypapophysis below floor of neural canal 30
Width of spinous process 26
7. Length of seventh cervical vertebra 37
Height of spine above floor of neural canal 46
Transverse diameter of ball 19
Vertical diameter of ball 20
Width of spinous process 27
Dorsal vertebrae.
There are thirty-five vertebrae between the cervicals and the first
non-rib-bearing vertebra, to which the pelvis was, evidently, attached.
The distinction between the cervicals and thoracics cannot be made from
any characters they possess, as the seventh vertebra does not bear a
distinct hypapophysis. Neither can it be said with certainty from this
specimen which is the first thoracic vertebra, as the cervical ribs
had, unfortunately, been displaced in the collection and preparation
of the specimen. In another specimen, referred to _C. pumilus_, and
which, as will be seen later, cannot be specifically distinguished
from the present species, short cervical ribs were found attached to
six vertebrae posterior to the atlas. That the eighth vertebra is a
thoracic one is shown by the relation of the ribs in this specimen.
Posteriorly there is no distinction, also, between the true thoracic
vertebrae and those of the lumbar region. All the vertebrae anterior to
the pelvis bear ribs, and will all be considered as dorsal vertebrae,
the true thoracic vertebrae being restricted to those of which the ribs
are elongated, and, probably, connected with the sternum.
In the anterior vertebrae of the series, the centra are subcarinate
below, the obtuse, rounded ridge becoming less and less apparent
until no indications of the keel can be seen, before the middle
of the series. The transverse processes are stoutest, with a more
elongated, sigmoid articular surface, with little or no constriction,
and projecting only slightly beyond the stout articulating processes,
in the anterior vertebrae. In the tenth or eleventh, the articular
surface has become markedly smaller, more vertical, and less sigmoid in
outline. Thence to the last, the articular surface for the ribs remains
nearly the same. The process itself, however, becomes gradually more
prominent and constricted, as the zygapophyses becomes smaller. The
spinous processes increase slightly in length and breadth, and are only
slightly oblique throughout. In length, the centra increase gradually.
The vertical diameter of the ball increases gradually, while the
transverse diameter remains more nearly the same.
MEASUREMENTS OF THE DORSAL VERTEBRAE.
1. Length of centrum to rim of ball 38 millim.
Transverse diameter of ball 20
Vertical diameter of ball 19
Height of spine above floor of neural canal 48
Extent of articular surface of transverse process 30
Width of spine 28
4. Length of centrum to rim of ball 41
Transverse diameter of ball 20
Vertical diameter of ball 20
Height of spine above floor of neural canal 48
11. Length of centrum to rim of ball 41
Vertical diameter of ball 22
Extent of articular surface of transverse process 16
Width of spine 32
15. Length of centrum to rim of ball 41
Transverse diameter of ball 21
Vertical diameter of ball 24
20. Length of centrum to rim of ball 42
Vertical diameter of ball 25
Height of spine above floor of neural canal 58
24. Length to rim of ball 41
Transverse diameter of ball 22
Vertical diameter of ball 23
Height of spine 49
28. Length to rim of ball 40
Vertical diameter of ball 24
Transverse diameter of ball 23
Height of spine 54
32. Length to rim of ball 38
Vertical diameter of ball 25
Transverse diameter of ball 24
35. Length to rim of ball 37
Caudal vertebrae.
Immediately following the thirty-fifth rib-bearing vertebra there is
an abrupt change, the tubercular process for the rib giving place to
an elongated transverse process. From the position of the pelvis, it
is evident that the ilia were attached to the first pair of these.
Precisely this relation of pelvis to the vertebrae is found in such
lizards as the Monitor and Iguana, and it is probable that such is the
relation in all the Pythonomorpha. It will thus be seen that there
are no distinctively lumbar vertebrae, if by such are meant free,
non-costiferous, pre-sacral vertebrae. The vertebrae of these animals
that have been so designated by writers are in reality basal caudal.
A distinctive term for them—those with transverse, non-costiferous
processes and without chevrons—is needed, and we propose,
provisionally, the term _pygial_. There are seven in the present
series, all characterized by elongated transverse processes, and not
differing much from each other. The vertebrae lie in the matrix with
the ventral aspect uppermost, concealing the spine and upper parts.
The under surface is somewhat flattened, and, as in the preceding
vertebrae, is gently concave antero-posteriorly. The transverse
processes are elongate, stout towards the base, apparently all of
nearly equal length, and directed gently backwards and downwards. In
the anterior vertebrae the processes spring from near the front part:
as the centra become shorter they arise from near the middle. In the
last one of the series there are minute indications of chevrons.
MEASUREMENTS OF THE PYGIAL CAUDAL VERTEBRAE.
1. Length to rim of ball 36 millim.
Width of ball 25
Expanse of transverse processes 130
Width of transverse process near base 17
2. Length to rim of ball 33
3. Length to rim of ball 31
4. Length to rim of ball 29
5. Length to rim of ball 28
6. Length to rim of ball 27
Expanse of transverse processes 130
Width of ball 24
7. Length to rim of ball 27
The centra of those caudal vertebrae which have chevrons do not differ
much in shape. They become less constricted, and, back of the middle of
the series, are smoothly cylindrical in shape. The transverse processes
decrease gradually in length, disappearing entirely in the twenty-fifth
or twenty-sixth. The spinous processes are more or less incompletely
preserved in the anterior vertebrae. They increase only gradually in
length for the first twenty of the series, and are markedly oblique,
with the posterior border stout, and the anterior border alate. With
the twenty-sixth they begin to increase more rapidly in length, and
have become more nearly vertical in position, and are thinner at each
margin. In the thirty-fifth or thirty-sixth they attain their greatest
length, and are here directed slightly forwards. Thence to the end of
the tail, the length decreases gradually, and, in position, they are
directed more and more obliquely backward. The chevrons are strongly
oblique throughout the series and are firmly co-ossified with the
centrum.
The tail, it is thus seen, has a broad, vertical, fin-like extremity,
which, doubtless, aided much in the propulsion of the animal through
the water.
There are sixty-seven vertebrae with chevrons present in the specimen,
all continuous, except in one place. The last one is less than
one-fourth of an inch in diameter, and shows that there had been yet
another, possibly several more. Toward the base of the series the tail
has been bent forwards over the back, and it is possible that, where
the break occurs, there has been a vertebra lost. The measurements,
however, do not seem to indicate any loss. The entire series of
vertebrae was not less than sixty-eight, and probably not more than
seventy, making for the entire vertebral series one hundred and
seventeen to twenty.
MEASUREMENTS OF THE CHEVRON-BEARING CAUDAL VERTEBRAE.
1. Length to rim of ball 26 millim.
5. Length to rim of ball 24
Vertical diameter of ball 21
Transverse diameter of ball 24
10. Length to rim of ball 24
15. Length to rim of ball 24
Height of spine above floor of neural canal 40
Length of chevron 45
20. Length to rim of ball 23
Vertical diameter of ball 21
Transverse diameter of ball 22
25. Length to rim of ball 20
Height of spine 44
Width of spine at base 19
Width of spine at distal end 10
Length of chevron 85
Altitude of tail 112
30. Length to rim of ball 18
Vertical diameter of ball 17
Height of spine 57
Width of spine at base 19
Width of spine at distal end 9
Length of chevron 99
Altitude of tail 20
35. Length to rim of ball 16
Vertical diameter of ball 16
Height of spine 61
Length of chevron 97
Altitude of tail 122
40. Length to rim of ball 15
Vertical diameter of ball 15
Height of spine 54
Length of chevron 70
Altitude of tail 110
45. Length to rim of ball 14
Vertical diameter of ball 14
Height of spine 40
Length of spine 50
Length of chevron 58
Altitude of tail 93
50. Length to rim of ball 13
Length of spine 43
Length of chevron 55
Altitude of tail 73
55. Length to rim of ball 12
Length of spine 38
Length of chevron 42
Altitude of tail 63
60. Length to rim of ball 9
Length of spine 46
Length of chevron 25
Altitude of tail 50
66. Length to rim of ball 7
Length of chevron 10
Altitude of tail 20
67. Length 6
Ribs.
As has already been stated, the cervical ribs were displaced in the
present specimen, and measurements of them cannot be given. In a
smaller specimen, specifically indistinguishable from the present one,
the entire cervical series is preserved with the ribs attached. The
first, that articulating with the axis, is very short. The following
ones are stouter, but increase only moderately in length, that of the
sixth measuring only thirty-five millimeters, while that of the seventh
is but a little longer. In the specimen of _C. velox_ described,
there is a detached cervical rib sixty-five millimeters in length; it
probably belongs with the seventh.
The thoracic ribs are simple, somewhat flattened rods, moderately
expanded at the proximal end. The greatest convexity is shown about the
middle of the series, where the versedsine of the curvature is forty
millimeters, the chord being one hundred and sixty. Posteriorly, the
short ribs are only gently curved.
Lying by the side of the vertebral column, and between the ribs,
as they have been pressed down, are a number of flattened, soft,
punctulate bones, which are evidently the costal cartilages.
Posteriorly four rows of them are seen, lying closely side by side,
some of them eight or ten inches in length. The sternum, composed
of the same material, has been so crushed and crumpled that its
shape cannot be made out. The whole structure here, whether of ribs,
cartilages or sternum, reminds one very strongly of such lizards as the
Iguana or Monitor. There is no indication, however, in any specimen, of
an episternum.
MEASUREMENTS OF RIBS.
Length, first thoracic rib, (chord) 200 millim.
Length, eleventh thoracic rib, (chord) 145
Length, thirteenth dorsal rib 68
Length, eighteenth dorsal rib 64
Length, thirty-fourth dorsal rib 52
The lengths of the different regions, as they lie in their natural
relations, are as follows:
Skull 0.420 meters.
Neck 0.225
Trunk 1.360
Tail 1.460
Total 3.465 11 ft. 7 in.
The measurements of an excellent specimen of _C. tortor_ are as follows:
Skull 0.630 meters.
Neck 0.360
Trunk, (thirty-three vertebrae preserved) 2.370
A very complete specimen of a _Liodon_ in the Museum, in which the
_complete_ vertebral column is present, numbering one hundred and
seventeen vertebrae, gives the following measurements. The skull is
complete, save the most anterior portion.
Skull (approximated within narrow limits) 0.700 meters.
Neck 0.430
Trunk 1.760
Tail 3.420
Total 6.310 20 ft. 8 in.
The vertebral series in this specimen is composed of seven cervicals,
twenty-three dorsals, seven pygials, and eighty chevron-caudals.
The relative proportions of the different regions in the two genera,
as shown by the two specimens of _Clidastes_ and _Liodon_, may be
represented as follows. The first column is for _Clidastes_.
Skull 12.1 11.1
Neck 6.5 6.8
Trunk 39.2 28.0
Tail 42.3 54.1
Limbs.
The figures in plates II and III will give a sufficiently good idea
of the limbs in this specimen. They are figured as they were lying,
showing the outer sides of the coracoid, scapula and pelvic bones, and
the palmar or plantar surface of the remaining bones.
Coracoid.
It will be observed in plates II and IV that there are two very
different types of coracoid, one with a deep emargination, the other
without the slightest indication of such. The same non-emarginate
form occurs in _C. tortor_, as specimens in our Museum show, in _C.
propython_ Cope (Ext. Batr. etc. pl. xii, f. 16,) and in _C. dispar_,
as figured by Marsh[7], and as stated by him in the same paper
(“There is certainly no emargination in the coracoid of _Clidastes_,
_Edestosaurus_ and _Baptosaurus_, as specimens in the Yale Museum
conclusively prove.”) It is true that Marsh in a later paper[8] figured
a specimen with emarginate coracoid under the name of _Edestosaurus
dispar_, but it is certain that his identification of his own species
was wrong, as will be seen by comparing his figures. From the senior
author’s memory of the specimen with the emarginate coracoid figured,
and from the figure itself he feels confident that the second specimen
is _C. velox_.
[7] Amer. Journ. Sci. iii, pl. xi, f. 1, June, 1872.
[8] Amer. Journ. Sci. xix, pl. i, fig. 1, Jan., 1880.
That the emargination was overlooked by the author seems strange, as
in the same paper in which this figure is given occurs the description
of _Holosaurus, founded upon that very character_. If the emargination
is sufficiently important to base a genus in the one case, then it
should be in the other, and the character could not be applied to
_Edestosaurus_, based upon characters which it hardly seems possible
that the author himself could seriously consider, for _E. dispar_ was
the type of _Edestosaurus_.
It will be observed, further, that the figured coracoids differ very
materially in size, those with the emargination pertaining to a small
species, while _C. dispar_ is one of the largest. In our Museum there
are three specimens with the emarginate coracoid, all of them small or
very small, the described specimen of _C. velox_ being the largest.
The point of chief interest in this relation is the value that can be
given to this character. Is it individual, specific or generic? Marsh
has called it generic, but we think an examination of the two very
complete specimens of _C. tortor_ and _C. velox_ in our Museum will
convince any unprejudiced student that he is in error.
A comparison of the figures herewith given of the paddles will show
their great resemblance, and these two forms of paddles have been
figured because the species are the most unlike of any that we know in
the genus. As all the small specimens seem to possess this character,
and as they cannot be called immature specimens, we believe the
character is a specific one. As Marsh says, typically both _Clidastes_
and _Edestosaurus_ have a non-emarginate coracoid, so that neither name
could apply to the emarginate form, were it generically distinct.
Our Museum also contains both forms of the coracoid pertaining to the
genus _Platecarpus_, of which _Holosaurus_ is a synonym.
While studying the specimen above described, a striking similarity was
observed to several other specimens already determined with confidence
as _C. pumilus_ Marsh. A more careful comparison failed to bring out
any real differences beyond size, and even this was shown to be very
inconstant.
The following comparison of the descriptions given by Marsh will be of
interest.
_C. pumilus._
TEETH. Nearly round at base somewhat curved
and with smooth enamel.
QUADRATE. The rugose knob near the distal
end of the quadrate is similar to that in _C.
Wymani_ (just below the posterior superior process
is a prominent rugose knob with a deep pit under
it), but has no articular pit under it. The hook
is comparatively short and has a free compressed
extremity. The articular margin is not deflected
toward the meatus.
CERVICAL VERTEBRAE. Articular face nearly
vertical, and having a broad transverse outline with
faint superior emargination. The hypapophysis stout
and transversely triangular.
_C. velox._
Premaxillary and maxillary teeth smooth and
subcompressed.
The great ala less curved than in _E. dispar_, concave
transversely on both surfaces. The alar process has
its articular process very narrow in its extension
over the great ala. No notch in posterior margin of
external angle. On the ridge below the angle and
nearly opposite the meatal pit is a strong rugosity
which is rudimentary or wanting in _C. dispar_. The
posterior margin of the hook is only a narrow tongue
projecting towards the meatal pit, instead of a broad
articular surface.
Articular face transverse.
The description, otherwise, shows no discrepancies of importance. The
chief difference given by the author is the size, and this character
we think our specimens show to be of little specific value. “It
is a question of some importance how far difference in size among
the Mosasauroids may be a test of difference in species. Among the
numerous remains of these animals which have been discovered I have
never yet observed any which presented any evidence relative to age.
* * * In this view of the case, some of the many described species of
Mosasauroids may have been founded on different sizes of the same.”[9]
[9] Leidy, Rep. U. S. Geol. Surv. Hayden, vol. i, p. 284.
The length of the cervical vertebrae in the specimen above described
is thirty-seven or thirty-eight millimeters. The cervical vertebrae in
two specimens referred to _C. pumilus_ have lengths respectively of
twenty-two and thirty millimeters. In the type specimen of _C. velox_
they must have had a length of at least forty-two millimeters.
It thus appears that, between the smallest specimen, which, in life,
could have hardly exceeded eight feet in length, our specimens,
indistinguishable anatomically, represent forms of ten and twelve feet,
while the type itself was about fifteen feet in length.
Of the material originally referred to _C. pumilus_, there are in the
collection five or more specimens, which, altogether, furnish nearly
every part of the skeleton. They present no tangible differences from
the skeleton of _C. velox_ described above. There can be, hence, little
or no doubt but that the name _C. pumilus_ is a synonym.
It is hardly possible to say with certainty that _C. affinis_ Leidy
is or is not the same as _C. velox_, but, so far as the description
goes, we can find few differences. The type is of about the same size
as the type of _C. velox_, and the figures agree well with the bones
of the skeleton described. Although the description was not published
till 1873, the author makes no mention of the species of Marsh’s. Leidy
describes the back teeth as having the enamel strongly striated, with
the surface presenting evidences of subdivision into narrow planes. In
this respect, only, it disagrees with the specimen.
_Plioplatecarpus_ Dollo is described by its author as having a sacrum
of two conjoined vertebrae,[10] by reason of which it is placed in
a separate family from the rest of the _Pythonomorpha_. It may be
presumptuous to express a doubt of the genuineness of the sacrum, and
yet, save from the fact that the author found two specimens quite
alike, one might doubt it strongly. It is not very rare that two, or
even three vertebrae are found united from injury in these animals,
and such would readily account for the consolidation as figured and
described by Dollo, except for the coincidence of the second specimen.
A stronger reason for doubt is the statement that the consolidated
vertebrae belong to the posterior “lumbar” region, and that the last
vertebrae had small tubercles indicative of chevrons. In the reptiles
which we have examined, the chevrons do not begin immediately behind
the pelvis, but are separated by a longer or shorter region in which
the vertebrae bear elongated diapophyses alone. If the conjoined
vertebrae figured by Dollo are in reality sacral, it would appear
that the animal is an exception to _Clidastes_ and such lizards as we
have examined. Furthermore, the pelvis must have been of a different
structure from that in the Kansas genera of the Pythonomorpha, for, in
these, it is evident that the ilium had an oblique position, and could
have been attached to but a single diapophysis.
[10] Bull. Su. Mus. Roy. S. Hist. Nat. d. Belg. i, p. 8, 1882.
CLIDASTES WESTII, N. SP.
A specimen of much interest in the University collection differs so
markedly from the other forms represented by specimens, as also from
the descriptions of the known species, that we are constrained to
regard it as new. It was collected by Mr. C. H. Sternberg from the
uppermost of the Niobrara beds, in the vicinity of the old town of
Sheridan. The character of the associated invertebrate fossils seems
to indicate a different geological horizon, either the Fox Hills
group, or transition beds to that group. The specimen consists of a
complete lower jaw, quadrate, portions of the skull, the larger part
of the vertebral column, and the incomplete hind and fore paddles. The
vertebrae preserved are in two series, the one, numbering thirty-three,
continuous with the skull; the other, sixty-three in number, all
chevron caudals. The terminal caudals preserved indicate that there
were several more in life, perhaps five or ten; the first of the series
was evidently among the first of those which bore chevrons. Altogether
the tail may have had seventy-five chevron caudals. The lengths of
the two series are respectively seventy-one and seventy-two inches.
Assuming that there was the same number of precaudal vertebrae as in
_C. velox_, the entire vertebral column would have measured in life
fifteen feet and four inches. The lower jaw shows the skull to have
been very nearly twenty-four inches in length, making, for the animal
when alive, a length of seventeen and one-half feet. This is one of
the largest species, and it is interesting to observe that the real
size here, as usually elsewhere among fossil vertebrates, is less than
supposed. It is doubtful whether there is a _Clidastes_ known that
exceeded twenty feet in length.
While the skeleton was only about one half longer than the specimen
of _C. velox_ described in the foregoing pages, or of about the same
length as a very complete specimen of _C. tortor_ in the museum, the
proportions of the animal were very much stouter. The figures given in
plate VI of the twenty-fifth, or eighteenth dorsal, vertebra will show
the relations between length and breadth: it is upon these remarkably
stout proportions, and the shape of the articular faces, as indicated
by the figures and by the measurements appended, that the species is
chiefly based. The articular surfaces of the basal caudal vertebrae are
remarkably triangular in shape, with the angles rounded, and the sides
of nearly equal length. This triangular shape is persistent for the
first twenty of the series as they are preserved. The paddles, as shown
in plates IV and V, show much stouter proportions than in either _C.
velox_ or _C. tortor_.
The species comes nearest to _C. stenops_ Cope, but it seems hardly the
same. It is, also, evidently allied to _C. dispar_ Marsh. From these
and other described species, the following, extracted from the original
descriptions, will serve to show the differences, in comparison with
the specimen of _C. Westii_.
=C. dispar.=
The articular faces in the cervicals are a broad transverse oval,
faintly emarginated above for the neural canal. In the dorsals and
lumbars the cup continues transverse, and the emargination is deeper,
but in the anterior caudals the outline becomes a vertical oval. There
appears to have been thirteen mandibular teeth.
Length of axis with odontoid process 32 lines 100
Width between diapophyses 26.8 103
Length from edge of cup to end of ball in
eleventh vertebra 25 100
Width of ball 14 56
Depth of ball 12 43
=C. Wymani.=
In the cervical vertebrae, the outline of the articular faces is
transversely cordate. The centra of the anterior dorsals are elongate,
and much constricted behind the diapophyses. In the anterior caudals,
the articular faces are a broad vertical oval.
Length of axis with odontoid process 19 lines 100
Width between diapophyses 17 89.4
Width of ball 8 42.1
Depth of ball 7 36.7
Length of sixth cervical, without ball 13 100
Width of cup 9 69.1
=C. rex.=
The cervical vertebrae have very broad, transversely oval faces, with
indications of emargination. The dorsals are elongated, with transverse
faces, and a distinct superior excavation for neural canal. The
articular ends of the anterior caudals are vertically oval.
Length of posterior cervical vertebrae 44 mm 100
Vertical diameter of ball 24 54.5
Transverse diameter 29.5 67
Length of a dorsal vertebra 52
=C. stenops.=
The anterior caudals possess wide diapophyses. Their articular faces
are a vertical oval, a little contracted above, sometimes a straight
outline. They present a peculiarly elongate form.
Length of axis (alone) 60 mm 100
Vertical diameter of ball 27 45
Transverse diameter of ball 27 45
Length of the mandible 720 100
Depth at coronoid process 150 20.9
MEASUREMENTS OF CLIDASTES WESTII.
Length of dentary 400 millim.
Depth opposite the first tooth 20
Depth opposite last tooth 62
Entire extent of mandible 630
Greatest depth at coronoid process 95
2. Length of axis with odontoid process 80
Length of axis without odontoid process 70
Vertical diameter of ball 24
Transverse diameter of ball 33
4. Length of fourth cervical vertebra to rim of ball 49
Expanse of diapophyses 82
5. Length of fifth cervical to rim of ball 49
Transverse diameter of ball 35
Vertical diameter of ball 28
Expanse of diapophyses 90
8. Length of eighth vertebra to rim of ball 53
Expanse of diapophyses 90
14. Length to rim of ball 54
Transverse diameter of ball 40
Vertical diameter of ball 33
Expanse of diapophyses 100
18. Length to rim of ball 50
Transverse diameter of ball 40
Vertical diameter of ball 36
Expanse of diapophyses 100
23. Length to rim of ball 50
Transverse diameter of ball 41
Expanse of diapophyses 100
25. Length to rim of ball 52
Transverse diameter of ball 43
Vertical diameter of ball 43
Expanse of diapophyses 100
30. Length to rim of ball 54
Transverse diameter of ball 46
This species is named in memory of Judge E. P. West, lately deceased,
to whom our Museum owes so much for his long, diligent and faithful
labors in the collection and preparation of the geological material.
* * * * *
ERRATUM: P. 17, line 15, for “_Edestosaurus_,” read
_Clidastes_, and in next line, strike out “Proc. Acad.” etc.
Notes and Descriptions of Syrphidae.
BY W. A. SNOW.
WITH PLATE VII.
Among the insects obtained by Prof. F. H. Snow in a recent trip to
Colorado, is an excellent representative collection of the Diptera.
The material for the following notes on Syrphidae is chiefly drawn
from this collection. That such a collection affords so many points of
interest in this, one of the best studied families of North American
Diptera, is an evidence of the rich field that is presented by this
important and little-studied order of insects.
CALLICERA.
_Callicera_ Panzer, Fauna Germanica, 1806.
_Callicera_ is a small genus hitherto supposed to be peculiar to
Europe. The species are found in the high mountains, where the males
are often taken while hovering in the air. The present collection
includes numerous specimens of a species taken near the summit of Mt.
Deception, in Manitou Park, Colorado, at an altitude of nine thousand
feet.
The occurrence of members of this genus in the western part of the
United States is a fact of especial interest and further substantiates
the rule that American forms common to Europe are more apt to occur
in the western regions. _Arctophila flagrans_ Osten Sacken, is a case
precisely similar to the present one, belonging as it does to a small
European genus of mountain flies, and described from Colorado.
As the genus is a new one to our fauna, I here give an amended
transcription of the generic characters from Schiner’s Fauna Austriaca,
to include the new species, which differs only in unimportant details.
=Callicera.=
Rather large, stout, green or black species with metallic lustre and
abundant, long pile. Head hemispherical, somewhat broader than the
thorax. Antennae porrect, longer than the head, somewhat remote at
their base, inserted upon a protuberance of the front; first joint
sometimes elongate; second joint shorter than, or as long as, the first
joint; third joint one to three times the length of the first two
joints taken together, with a short, terminal style. Face broad, under
the antennae concave in profile; an obtuse tubercle below the middle;
on the sides thickly covered with pile. Proboscis rather prominent,
with broad labella. Eyes hairy, holoptic in the male. Abdomen
elliptical, as long or longer than the thorax. Legs moderately strong.
Third longitudinal vein straight, first posterior cell distally short
petiolate; marginal cell open; cross-vein situated near the middle of
the discal cell, oblique.
=Callicera montensis, n. sp.=, Plate vii, f. 4.
MALE. Black, densely golden red pilose. Frontal triangle, face
and cheeks deep black, shining, covered thickly with black pile, save
a median facial stripe. Antennae black, basal third of third joint on
the under side red; first joint short; second joint not more than half
as long as the first; third joint three times as long as the first and
second joints taken together; gradually broadened for a third of its
length, and then attenuated; style white. Eyes thickly clothed with
golden pile. Thorax and abdomen covered everywhere with long golden
red pile. Legs black; tarsal joints below and at their articulations
reddish. Wings nearly hyaline, brownish on the anterior basal portion;
stigma yellow.
Length 11 millimeters. Three specimens, Colorado.
The genus may be distinguished from _Pelecocera_, in Williston’s
dichotomic table of the genera of North American Syrphidae, by the
pilose eyes.
=Microdon megalogaster, n. sp.=, Plate vii, f. 1.
MALE. Large, yellowish pilose species, in shape globose.
Antennae reddish black, the first joint about as long as the following
two together; second joint not one-third as long as the third. Face
dark metallic green, shining, thickly covered with golden yellow
pile. Front black, with similar pile, narrowed in the middle. Eyes
bare. Thorax and scutellum deep metallic green, with long, thick,
golden pile; scutellum gently emarginate, the small obtuse tubercles
approximate. Abdomen short and broad, black, moderately shining; first
two segments and the hypopygium somewhat green; pile at base yellow,
elsewhere short, black. Legs black, with black pile; front tibiae
and their metatarsi, on the inner side, with short golden pile; hind
metatarsi incrassate and longer than the three following joints taken
together. Wings uniformly subinfuscate; veins at the outer part of the
first posterior and discal cells sinuous and rounded.
Length 12 millimeters. One specimen.
=Chrysotoxum derivatum= Walker.
Eight specimens from Colorado, which vary not a little from each
other and from Williston’s description. They seem to belong here,
however, better than elsewhere. In one specimen, the second joint of
the antennae is shorter than the first, and only one-fourth the length
of the third. In five examples the second abdominal cross-band is
not interrupted; in the others it is distinctly parted. In two, the
third band does not reach the yellow of the broad hind margin; in two
others it barely touches it; in five, the two bands broadly coalesce.
The yellow of the fifth segment, in four specimens, incloses a black,
inverted V; in two others an inverted Y.
=Paragus bicolor= Fabr.
Three specimens, Colorado. These may be located under Schiner’s variety
_taeniatus_.
=Melanostoma stegnum= Say.
_Syrphus stegnus_ Say, Journ. Acad. Phil. vi, p. 163.
_Melanostoma tigrina_ Osten Sacken, Western Diptera, p. 323.
_Melanostoma stegnum_ Williston, Biol. Centr.-Amer. Diptera,
iii, p. 10.
Eleven specimens, Colorado, which answer well to the descriptions. The
metallic band of the fourth abdominal segment is sometimes interrupted,
and there is usually a triangular opaque black spot near the anterior
border of the fifth segment. “The female, hitherto unknown, has the
front broad above, pollinose, except on the upper part, and with black
pile; the thorax more shining metallic blue; the tibiae yellow, and
on the third and fourth abdominal segments there is a narrow shining
stripe, bisecting the black, as in the fourth segment of the male.
The male has some long black hairs on the outer side of the front and
middle tibiae, which are inconspicuous in the female. It is evident,
from the lighter color of the tibiae, that Say’s specimens were
females.” Williston, l. c.
=Melanostoma mellinum= Linne.
A single female specimen from Manitou Park.
=Melanostoma, n. sp.=?
MALE. Face and front dark metallic blue, shining, thinly
covered with light-colored pollen; tubercle and epistoma black,
shining, the former small. Antennae black, third joint yellowish red
below, oblong. Pile of frontal and vertical triangles dusky. Thorax
bronze-black, shining, sometimes bluish black, the pubescence white.
Halteres yellowish. Abdomen long and narrow, with almost parallel
sides; first segment metallic blue, shining; second segment opaque,
or subopaque, black, with a light metallescent scallop on the sides,
reaching to the distal third of the segment; third and fourth segments
similar, marked anteriorly by a wide, interrupted, or subinterrupted
blue fascia, deeply and widely emarginated, or concave behind; hind
border of the third, and sometimes of the second segment, narrowly
brown; fifth segment and the hypopygium metallic bluish green; sides
of the abdomen with silvery white pile, longest and thickest at the
base; the blue marking are whitish pruinose. Femora, except the tip,
a broad ring on the tibiae, and the four posterior tarsi, black;
elsewhere brownish or yellowish. Wings hyaline, stigma yellowish.
Length 7-8 millimeters.
=Eupeodes volucris=, Osten Sacken.
Numerous specimens, Colorado.
=Syrphus arcuatus= Fallen.
Four specimens, Colorado. These specimens vary not a little from each
other, and somewhat from the descriptions. One female is very small,
not over seven millimeters in length, and with the spots on the third
and fourth abdominal segments hardly oblique. One male has the hind
femora black as far as the tip, while in three females the black does
not extend beyond the middle.
=Syrphus disjectus= Williston.
A single female specimen, from Colorado, agrees well with the
description drawn from males. The pile of the thorax is more whitish
than orange-yellow, and there are light colored lateral margins on the
anterior part of the thorax.
=Syrphus ruficauda, n. sp.=, Plate vii, f. 3.
MALE. Eyes bare. Face greenish yellow on the sides, yellow in
the middle; a rather broad black line marks the border of the mouth
and is lost in the black of the cheeks. Frontal triangle yellow, with
long black pile. Antennae dark brown, more or less reddish below.
Pile of occiput light yellow. Dorsum of thorax deep metallic green,
the scutellum olivaceous yellow; both with light yellow pile. First
segment of the abdomen shining black; second segment opaque black,
with the lateral margins and hind border shining, and with a broad,
yellow, interrupted band, not reaching the lateral margins; third
segment similar, but with the yellow band somewhat wider, interrupted
or subinterrupted and slightly bilaterally oblique; fourth and fifth
segments orange-red, the sides narrowly black; the fourth segment shows
indistinctly a broad interrupted band of a somewhat lighter color,
corresponding to the yellow bands of the preceding segments. Legs light
brown; basal third of the front and middle femora and basal half of the
hind femora black. Wings hyaline, stigma yellowish.
FEMALE. Head wanting. Thorax purplish brown. The yellow band
on the second abdominal segment narrower, the second band straight,
narrower and interrupted. Legs light brown, except the proximal end of
the femora, which is black.
Length 9 millimeters. Three males and one female, Colorado.
=Syrphus pauxillus= Williston.
Two specimens from Colorado undoubtedly come here. The species was
described from a single male specimen. A female specimen offers the
following differences or additions: Length nine millimeters, mesonotum
more greenish black or bronze, the pile obscure whitish; fifth
abdominal segment without yellow spots on the anterior angles; legs
yellow, with the basal half of the front and middle femora, the hind
femora except the tip, a broad band on the hind tibiae, and the hind
tarsi, black.
=Syrphus ribesii= Linne.
Five specimens, Colorado.
=Syrphus americanus= Wiedemann.
Numerous specimens, Colorado.
=Syrphus umbellatarum= Schiner.
Five female specimens, Colorado. The only western locality heretofore
given is Arizona (Williston).
=Allograpta obliqua= Say.
Five specimens, Colorado.
=Mesogramma marginatum= Say.
Numerous specimens from Colorado, showing very great variation.
=Sphaerophoria cylindrica= Say.
Twenty specimens, Colorado. I think the specimens belong here,
though a positive identification is hardly possible at present.
=Rhingia nasica= Say.
One specimen, Colorado. This is the first time that this species
has been recorded from beyond the Mississippi.
=Copestylum marginatum= Say.
Two specimens, Colorado, representing the extremes of variation in the
species. The male corresponds to _C. lentum_ Williston. Specimens of
this species were bred from _Opuntia missouriensis_, in company with
others of _Volucella fasciata_ Macq.
=Sericomyia militaris= Walker.
Sixteen specimens from Minnesota and Colorado vary in the markings of
the second abdominal segment, and in the color of the legs. Some have
no spots at all on the second segment; in others the two yellow dots
are conspicuous, approaching, in size and shape, the markings of the
third segment. The tibiae vary from light yellow to reddish brown.
=Brachyopa cynops, n. sp.=, plate vii, f. 2.
Head light yellowish brown, largely concealed beneath light glistening
pollen; the shining ground color shows just above the antennae and in
a stripe on the cheeks, extending from the eye to the mouth opening.
Antennae wanting. Dorsum of thorax brown, covered with grayish pollen;
anteriorly with two approximated, linear, blackish stripes; laterally
with a broad, interrupted stripe. Scutellum light brown, with yellowish
pollen. Abdomen but little longer than broad; yellowish gray pollinose;
second segment with a circular brown spot in the anterior corners; the
two following segments are marked with corresponding elliptical spots,
and, in the middle of the anterior border with a triangular spot; on
the fifth segment are two small round spots. Legs uniformly reddish
brown, with light colored pollen and short whitish pile. Wing hyaline,
distinctly clouded at anterior cross-vein, on the veins at the anterior
outer corner of the discal cell and on the ultimate section of the
fourth vein; posterior cross-vein about as long as the penultimate
section of the fourth vein, the included angle obtuse.
Length 5 millimeters. One specimen, Colorado.
=Eristalis latifrons= Loew.
Numerous specimens, Colorado. The commonest Syrphid of the mountain
meadows. Some specimens have very indistinct brownish spots on the
second abdominal segment, and, when this is the case, the middle of the
wing generally shows a brown spot, and brown clouds along the anterior
veins between the spot and the base of the wing.
=Eristalis brousi= Williston.
One male specimen, Colorado.
=Helophilus latifrons= Loew.
Numerous specimens, Colorado.
=Xylota flavitibia= Bigot.
Eight specimens, Colorado. The glistening pile of the face and front
varies from white to a golden yellow. On the dorsum of the thorax
purplish stripes are distinctly visible. The fourth segment of the male
abdomen is often red, as in the female abdomen.
=Syritta pipiens= Linne.
Eight specimens, Colorado.
=Criorrhina umbratilis= Williston.
A single, male specimen, collected by Mr. W. J. Coleman, at Lawrence,
and agreeing exactly with the description. The only other known
specimen of this species is the type, at Washington, from Connecticut.
=Spilomyia quadrifasciata= Say.
Seven specimens, Lawrence, Kansas, (F. H. Snow and E. S. Tucker). The
species has not hitherto been recorded west of New York.
Notes on Melitera Dentata Grote.
BY VERNON L. KELLOGG.
WITH PLATE VIII.
At the meeting of the Entomological Club of the A. A. A. S., held in
August, 1891, at Washington, Dr. Riley called attention to the habits
of _Melitera prodenialis_ Walker. The larvae burrow into and feed upon
the fleshy leaves of the prickly pear, _Opuntia_. Dr. Riley’s specimens
came from Florida. Prof. J. B. Smith has recently bred the moth from
the prickly pear in New Jersey. His notes were presented at the same
meeting of the Club, and the brief references to the interesting
notes of Doctors Riley and Smith, made in the Canadian Entomologist
(v. xxiii, num. 11, pp. 242 and 256), suggest the presentation of the
following notes on _Melitera dentata_ Grote, the western species of
this Phycitid genus.
Chancellor F. H. Snow, of this University, while investigating a
grasshopper “outbreak” (_Dissosteira longipennis_) in eastern Colorado
in July, 1891, noted the withered and dying condition of many leaves
of the common prickly pear cactus (_Opuntia missouriensis_), and
on examining the leaves found in them certain large, naked, bluish
larvae. The larvae were imbedded in the fleshy leaves, eating away the
soft inner tissue. The hollowed-out spaces were nearly filled with
irregularly spherical, yellowish, translucent casts. The attacked
leaves were withered and brown without. Prof. Snow took a few leaves
and larvae on July 16, near Arriba, Colorado, and brought them to the
laboratory.
The larvae were put into breeding-cage on July 18. On July 28 one
larva had spun up and pupated in a corner of the cage behind a small
porcelain dish. Another had made a cocoon in a broken, empty pupa-case
of _Eacles imperialis_, but died before pupating. On August —— the
adults appeared, and have been determined by Prof. J. B. Smith as _M.
dentata_, Grote. As I am aware of no description of the earlier stages
of this species, I record the following notes of description:
EGG. About 1-1.2 millimeters in diameter, surface with broad,
meridian-like furrows from one pole for about one-third of the distance
to the other pole. Color, creamy white.
LARVA. Food plant, _Opuntia missouriensis_, prickly pear
cactus, burrowing into the fleshy leaves and eating the soft,
succulent, inner tissues. Length, 40 millimeters. Five pairs of
prolegs. Color, one specimen, ultramarine blue; skin, semi-transparent
and shining anteriorly, dead blue on dorsum; second specimen, buffy
with a bluish suffusion, blue between segments, prolegs bluish, and
last abdominal segment blue, especially below; skin more opaque than
in first specimen. No pronounced markings of skin; spiracles shining
black and present on first thoracic and first to tenth abdominal
segments. Head flattened, slightly narrower than first thoracic
segment, umber. Prothoracic shield well marked, brownish black; anal
shield, smoky brownish. Clothing, limited to tubercled hairs sparsely
distributed as follows: a subdorsal line of small tubercles, two
tubercles to a segment, each tubercle bearing three short, fine hairs;
a supra-stigmatic line, one tubercle to each segment, each tubercle
bearing three to four fine hairs; a similar infra-stigmatic line; a
sub-ventral line of tubercles, bearing usually four fine hairs, the
tubercles of the three thoracic segments in this line situated at base
of legs outside, and similarly as to the prolegs on the third to sixth
abdominal segments. The tubercles in all the lines are faintly smoky.
The larva is rather heavy, and rotund in form, tapering toward both
head and posterior segment. It moves with a lumbering gait, but rather
rapidly.
CHRYSALIS. Length, 20 millimeters; in cocoon of silk, loosely
covered with small dirt-masses. As made in the breeding cage the
cocoons were above ground, but concealed under or in available objects.
ADULT. The adults obtained from the breeding cage, (there
are no others in our collection), are easily distinguished from
_prodenialis_ Wlk., by the much stronger dentations of the outer line
of the primaries. Prof. Smith kindly sent a specimen of _prodenialis_
taken at Ocean Grove, New Jersey, for comparison. The row of marginal
black spots on the primaries which Hulst (Tran. Am. Ent. Soc., v.
xvii, p. 172) mentions as distinctive of dentata is as pronounced in
Prof. Smith’s specimen of _prodenialis_ as in our _dentata_. The much
lighter color of the primaries, head and thorax in dentata as mentioned
by Hulst is characteristic. An interesting feature in the venation of
the hind wings in our bred specimens of _dentata_ is the considerable
coalescence of the sub-costal and costal veins. Vein five is wanting,
as mentioned by Hulst. In addition, there is further departure from
a normal venation, in that vein seven after rising with six from its
stem, (Hulst says: “Six short stemmed with seven”), coalesces for a
short distance with eight and then runs free to the margin. Behind the
forking of seven and six the stem (remnant of sub-costal) unites with
the costal, and its basal portion is wholly merged with the forward
vein. This partial disappearance of the sub-costal seems to be shared
by _prodenialis_ and is probably characteristic of the genus.
Prof. Smith, as recorded in the Canadian Naturalist, v. viii, p. 242,
(1891), bred several specimens of _Volucella fasciata_, a Syrphid fly,
from the same prickly pear leaves in which the _Melitera_ larvae were
living. It is interesting to note that pupariae and later, adults of
_Volucella fasciata_ and _Copestylum marginatum_, a closely allied
Syrphid, were noted in the Opuntia leaves from which _M. dentata_ was
bred. (See note by Dr. Williston, Entomological News, v. ii, p. 165,
1891).
Diptera Brasiliana.
BY S. W. WILLISTON.