The itonid group of galls herewith presented can be distinguished with
one exception (No. 33) from the very common Phylloxera galls (Aphididæ)
by the fact that the latter forms which are sufficiently small to be
comparable in size to the itonids are intercalated in the leaf blade,
i. e. the gall extends more or less prominently from both sides of
the leaf. The itonids always give the appearance of an appendicular
structure attached to the leaf.
1. Gall on nut. Caryomyia nucicola. (3)
1. Gall on leaf. 2.
2. An apparent elongate enlargement of vein.
Cecidomyia cynipsea (?) (4).
2. An inrolled leaf edge. (2).
2. Galls arising from intervenal tissue between veins or immediately
adjoining veins; radially symmetric structures with principal axis
more or less perpendicular to leaf blade. 3.
3. Galls double-chambered as seen in vertical median section. 4.
3. Galls single chambered. 7.
4. Galls definitely depressed. (5).
4. Galls small, sub-globular. (6).
4. Galls definitely conic. 5.
5. Elongate gall with rounded base in definite visible socket. (7).
5. Shorter gall attached by pedicel from rounded base not articulating
with definite socket. 6.
6. Proximal chamber of gall, conic. (5).
6. Proximal chamber of gall, depressed. (8).
7. Galls definitely conic; forms having rounded bases, the distal
portion is sufficiently drawn out to place the cecidium under
this class. 8.
7. Galls spheric, sub-spheric or depressed. 15.
7. Galls sub-cylindric, 2½-3 times as long as wide. 22.
7. Galls obconic, i. e., part projecting from leaf is flat topped,
constricted proximally to the pedicel embedded in the leaf. 25.
7. Blister gall, intercalated in the leaflet, projecting on both
sides. Cecidomyia? sp. (33).
8. Small irregular, low, masses of tissue always in axils of principal
veins of leaflet. Eriophyes sp. (1).
8. Galls definite structures projecting prominently from leaf
surface. 9.
9. Conic gall generally with strongly recurved tip appearing as though
lying on side, decumbent. (9).
9. Galls erect or tilted, seldom bent over, however, beyond angle of
45. 10.
10. Gall with flattened sides, pyramid-like. (10).
10. Galls with sides flattened. 11.
11. Proximal half of gall conic, never sub-globular. (11).
11. Proximal half sub-globular. 12.
12. Galls smooth. 13.
12. Galls pubescent. 14.
13. Galls large, 4-7 mm. long. (12).
13. Galls small, 1½-4 mm. long. (13).
14. Trichomes very long coarse. (14).
14. Pubescence short, fine. (15.)
15. Galls attached by proximal pedicel embedded in leaf, as seen in a
median vertical section.
15. Galls attached by structure extending from leaf into base of gall,
which remains on leaf when gall falls. 20.
16. Walls thick, soft. 17.
16. Walls thin, 18.
17. Galls smooth, depressed or with upward flaring walls forming a
saucer or cup-shaped structure distal to the chamber. (16).
17. Gall globular, finely pubescent like that of a peach. (17).
18. Surface perfectly smooth, symmetrically sub-spherical galls. 19.
18. Surface minutely shagreen-roughened, gall asymmetric, one side
prominently extended laterally. (18).
19. Small galls, 2½ mm. dia., nipple expanded and flattened resembling
the end of a bottle. (19).
19. Larger gall, 3-4 mm. dia., nipple short, pointed. (20).
20. Thick-walled, particularly the distal end, covered with heavy
tawny pubescence. (21).
20. Thinner walled, pubescence very short, puberulent. 21.
20. Very smooth. (22).
21. Depressed (not over 3 mm. high) with column extending through
center of chamber. (23).
21. Globular, 4-5 mm. high. (24).
21. Definitely balloon-shape. (25).
22. Base embedded in socket. 23.
22. Base not embedded in socket. 24.
23. Round-conic at tip. Caryomyia tubicola. (26).
23. Tapering to point, horn-like. (27).
24. Small gall, 2-2½ mm. high, with flaring base, attached by minute
pedicel at center. (28).
24. Large gall, 5-6 mm. long, gradually constricted proximally to very
narrow neck at point of attachment. (29).
25. Distal face with fovea containing a central nipple. Leaf not
projecting on side opposite gall. (30).
25. Distal face with fovea, leading into central pore; no central
nipple. Prominent convexity of leaf on side opposite the gall.
(31).
25. Distal face flaring out at edge into radiate bracts; these
sometimes strongly incurved. (32).