This was published in 1861, and would accord entirely with w_Fossil Butterflies Memoirs of the American Association for the Advancement of Science, I.

of the butterflies of Aix and their nearest allies. But eleven years

later, after studying the great amount of material which had meanwhile

accumulated, Saporta seems to have reached different conclusions,

for in his _Revision de la Flore des Gypses d’Aix_ he states that the

affinities of the eocene vegetation of Aix are with southeastern Asia

and with Africa, and lists of analogous species are given, showing that

twenty-two Aix species are to be compared with similar types in Asia,

and forty with those of Africa. So that African forms much surpass the

Asiatic in the eocene flora of Aix. This is particularly true, he says,

with reference to the region of Africa between Abyssinia and the Cape of

Good Hope. “C’est là évidemment le pays qui nous offre le tableau le plus

ressemblant de ce que devait être le midi de la France, et c’est aussi

vers ce même pays, ne l’oublions pas, que nous avons été ramenés par

l’examen des autres élémens de la flore, spécialement par la proportion

relative des deux grandes classes et des familles prédominantes.”[AS]

The African element seems to be almost altogether wanting in the eocene

butterflies, while the Asiatic predominates. In a chart accompanying

Count Saporta’s paper, however, he represents the present limits of the

_principal genera_ noticed in the flora of the gypsum of Aix by means of

colored lines. These lines cluster remarkably along the southern borders

of Asia and extend over a large part of Africa and across the ocean to

America, and particularly toward the southern United States and the

Antilles. Based on the distribution of these principal genera alone, the

flora of the southern border of Asia would show a closer affinity to that

of eocene Aix than would that of any equivalent belt in Africa; and if we

may suppose that our relics of butterflies represent the principal genera

then existing, we should trace a somewhat similar chart, but for the

entire absence of African types; for subtropical American types mingle

with those of the Mediterranean district and especially with those of

the Indo-Malayan region. Count Saporta shows in his memoir just quoted,

as before, that the relations of the eocene flora of Aix to that of the

present Mediterranean basin were more restricted than its relations

to exotic types, but in a letter to me he writes: “Ces affinités [les

affinités présumées de la flore d’Aix] sont d’une part avec la région

Méditerranéen, de l’autre avec l’Afrique et les Indes orientales. Les

affinités miocènes avec l’Amérique sont postérieures.” These later

American affinities are, however, foreshadowed among the plants and

also, as we have seen, in the Pamphilites of eocene Aix. They appear

again, and very decidedly, when we reach the miocene itself, for the

affinities of the butterfly from Rott, and two of the later butterflies

from Radoboj (where first we meet with truly modern types), are certainly

with America in the first instance, and secondarily with the whole north

temperate zone. While the last of the Radoboj butterflies shows still the

remains of the earlier affinities of the Aix flora in finding its nearer

existing types in Africa and southeastern Asia. The results we reach in

considering the Aix butterflies are not, however, in accordance with

those drawn from the insects of the same locality by Professor Heer. He

writes:[AT]—

“A Radoboj, … on rencontre une plus forte proportion de formes

tropicales [than at Œningen].…

Cette faune des insectes s’harmonise parfaitement avec le flore

de Radoboj qui, ainsi que nous l’avons prouvé précédemment,

a un caractère plus méridional que celle d’Œningen; ce qui

s’expliquerait par sa plus grande ancienneté.

Comme il résulte des recherches de M. G. de Saporta qu’Aix

appartient à l’étage ligurien, on devrait s’attendre à y

rencontrer encore plus de formes tropicales qu’à Radoboj. C’est

tout le contraire, si bien qu’en m’appuyant sur la faune et

en voyant que Aix avait 10 espèces en commun avec Radoboj et

4 avec Œningen, j’avais rapporté précédemment les terrains

d’Aix à la même époque que ceux de Radobo; et je les avais

rangés dans le Mayencien. Quatre genres ont disparu.… Tous

les autres genres vivent encore dans la Provence, mais ce

sont, comme à Œningen, presque tous des genres qui occupent

une aire géographique très vaste.… On ne peut pas dire que la

faune des insectes d’Aix contredise positivement l’idée que

cette localité avait un climat sous-tropical, cas presque tous

les genres que l’on y a observés jusqu’à présent s’étendent

jusque dans la zône sous-tropicale, néanmoins cette faune ne

fournit que bien peu de preuves positives, tandis que, comme

M. de Saporta l’a démontré, la flore est riche en formes

méridionales.”

It should be remarked, however, that the insect fauna of Aix is as yet

little known; that these observations of the learned Zurich Professor

were founded upon a material exceedingly meagre, in comparison with

the present vast accumulations of the museums of Marseilles, Paris and

Aix; we may hope soon to become familiar with them through the careful

researches of M. Oustalet; and these will show that the beds of Aix are,

perhaps, even richer in fossil insects than those of Œningen.

The American affinities of the Rott butterfly are in entire harmony with

what is known of the other insects of the lignites of the Rhine, where,

says Professor Heer:[AU]—“On retrouve également des types américains, qui

appertiennent à l’Amérique tropicale et sous-tropicale.”

As to the flora of Radoboj, Professor Heer writes in the work just

quoted (p. 96): “Les plantes de la zône tempérée sont représentées

plus fortement qu’à Sotzka,” and of the latter place he says (p.

95), after speaking of types of the temperate zone: “Cependant ces

espèces se trouvent fort à l’arrière-plan en comparison des formes

tropicales et subtropicales, parmi lesquelles prédominent … les formes

indo-australiens; néanmoins les formes américains, loin d’y faire défaut,

sont représentées par des types assez nombreux et nettement accusés.” As

a whole, therefore, the affinities of the tertiary butterflies seem to be

precisely what we should have anticipated from a study of the vegetation

of the period.

We close this portion of our subject with a tabular view of the results

we have reached in considering the affinities of the tertiary butterflies

with living types, in which the countries, where the living allies of

the fossil forms are now found, are placed in the right-hand columns

according to the degree of affinity of their inhabitants to the tertiary

species against which they are placed.

+--------+------------+------------------------------------------------+

| | | DEGREE OF AFFINITIES. |

| |NAMES OF +--------------+------------+----------+---------+

| +------------+--------------+------------+----------+---------+

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| +------------+--------------+------------+----------+---------+

+========+============+==============+============+==========+=========+

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GENERAL RESUME, WITH NOTICES OF UNDETERMINED FORMS.

Nine well authenticated fossil butterflies are now known, all from the

European Tertiaries; five of these have been found in the gypsum beds of

Aix in Provence, southern France, belonging to the Ligurian, a division

of the upper eocene; one in the lignites of Rott in the Rhenish Provinces

of Prussia, belonging to the Aquitanian, or lower miocene; and three in

the marls of Radoboj in Croatia, Austria, appertaining to the Mayencian

or middle miocene. Our present knowledge, then, places the apparition of

butterflies towards the end of the lower tertiaries.

As a general rule the specimens thus far discovered are in a fair state

of preservation, and especially are those parts preserved which enable

us, with considerable confidence, to determine their exact affinities.

Three of these insects belong to the highest family of butterflies,

Nymphales, four to the Papilionidæ, and two only to the Urbicolæ. If it

be considered probable that the lowest of these families was the oldest,

we can reasonably account for the scarcity of its members in the tertiary

strata by the fact that their almost universally robust and muscular

frame enables them to maintain flight when they have lost all but the

merest stubs of wings. They would thus seldom meet their end by falling

into pools of water, or if at last they did, it would be with fragments

of wings whose affinities could not be traced. This supposition would be

strengthened on noticing that one of the two fossil forms classed here,

_Thanatites vetula_, belongs to a group of genera which comprises the

very feeblest flyers in the family; and by the further consideration that

two of the three fossil Nymphalids belong to the weak-winged Oreades.

Eugonia, as well as Pamphilites, were doubtless strong and bold flyers;

while the genera of Papilionidæ were moderately endowed. To proceed

further in the analysis of their structural relations, two of the three

Nymphales belong, as we have said, to the highest group of butterflies,

the Oreades, represented now by the dark brown butterflies of our

meadows; the remaining one to the Præfecti, a group of gaily attired

butterflies with angulated wings like our common thistle butterfly, the

cosmopolite. Of the four Papilionidæ, three belong to the Danai; two

of these three to the group Fugacia, represented by our common yellow

brimstone butterflies; the third to the Voracia, or white butterflies

of the garden, so destructive to cabbages and other cruciferous plants.

The fourth Papilionid belongs to the lower subfamily Papilionides; not,

however, to that group which contains our swallow-tailed butterflies, but

rather to an allied tribe, represented in America only by the Parnasii

of the Rocky Mountain region. The two Urbicolæ are divided between the

Hesperides and Astyci, the former closely related to the dingy, sylvan

hesperians of early spring, seldom seen but by the naturalist; the latter

to the tawny, brisk little skippers busy around the flowers in June.

But a single family of butterflies, then, is unknown in a fossil

state,—that of Rurales; and since this comprises, in the main, insects

of exceedingly delicate structure and of small size, their absence is

by no means unaccountable. Yet, as we shall see further on, there are

intimations of the presence of some of their caterpillars in amber, and

an obscure and doubtful reference to a fossil Polyommatus from the beds

of Aix.

If we enquire where the allies of these nine fossil butterflies are now

living, we must seek for those of four of them in the East Indies; for

those of three of them in America, and especially in that part lying on

the confines of the tropical and north temperate zones; for those of one

of them in the north temperate zone of both Europe-Asia and America; and

for those of one in the Mediterranean district; for those of two only,

therefore, out of the nine, or less than one-fourth, in the region where

the fossils were discovered. Analyzing this point still further, we

notice that three out of the four species whose living allies are to be

sought in the East Indies come from the older deposits of Aix, and that

only one of the two remaining Aix species shows special affinities to

American types; we thus find here, as among other insects and among the

plants, a growing likeness to American types as we pass upward through

the European tertiaries.

The study of the floras of the European tertiaries has proceeded so

far that in most cases we are able to find, in the very beds where the

butterflies occur, plants which we may reasonably judge to have formed

the food of these insects in their earlier stages. In but a single

instance is the family of plants, upon which it was necessary, or almost

necessary, to suppose the caterpillar fed, entirely absent from tertiary

strata; and since this family is the Cruciferæ, which in its very nature

could scarcely have left a recognizable trace of its presence, the

exception has no force.

After presenting these facts, for convenience sake, in a tabular form, we

will pass on to the enumeration of those fossils which have been referred

to butterflies, but whose exact position is still unsettled.

TABULAR VIEW OF FOSSIL BUTTERFLIES.

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|Coliates Proserpina Scudd.| —— | Scudder. | 1875 |

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|Pamphilites abdita Scudd. | —— | Scudder. | 1875 |

| | | | |

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| | | | |

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| | | | |

+--------------------------+---------+---------------+-----------------+

+--------------------------+---------+---------------+-----------------+

| | |(upp. Eocene). | Aix. |

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