1864.] 
481 
List of Illinois Oak-inhabiting Cynipid^ and their Galls. 
*}"*(■ GaJh upon Leaves. 
1. Black Oak (q.tinctoria.) Gall q. spongifica 0. S. or “Oak-ap¬ 
ple” (vernal). See above, pp. 458—9. 
Gall-fly, Cynips q. spongifica 0. S., and its dimorphous 9 autum¬ 
nal form C. q. aciculota 0. S. = G. confluens Harris, 1862 = C. con- 
fiuentus Harris, 1841. See above, pp. 443—452. 
Guest gall-fly, Synophrus Iseviventris 0. S. See p. 460 and below. 
2 . Red oak (q. rubra.) Gall q. inanis O.'S. (vernal). See above, 
pp. 458—9. 
Gall-fly, (7. q, inanis 0. S. = Callaspidia confluenta Fitch non 
Harris. See above, pp. 457—8 
Guest gall-fly, probably none. Galls like this and that of C. nu- 
hilipennis Harris, and q. palustris 0. S., which consist scarcely of 
anything else but a central cell and a thin rind, without any spongy or 
woody matter intervening, seem to produce no Guest gall-flies. 
8. Black OAK. Gall g'. p^7^^/a3 n. sp., (autumnal.) A dark blood-red, 
spherical, but somewhat depressed gall .06—.20 inch in diameter, its 
upper surface roughish and opaque and often divided by deep striae 
into 12—20 four- five- or six-sided compartments like the back of a tor¬ 
toise, growing on the upper side of the leaves, but partly projecting 
also on the under side in a flattened disk with a central nipple, both 
of them the color of the leaf. Never placed on the principal veins and 
containing only a single very large cell. Frequently two or more galls 
are confluent, and they then assume an ellipsoidal or irregular form and 
contain two or more cells divided by thin partitions. Preserves its 
shape and color well when dry. Its general appearance is like that of 
q. pisum Fitch, figured and described N. Y. Rep. II, §319, but that 
gall occurs on the white oak, and is said to grow on the under side of 
the leaves only and on their principal veins and to contain usually two 
cells. Filulve.^ however, in a few cases—say 1 out of 500—does grow 
on the under side of the leaf. Very abundant but local near Rock 
Island, Illinois. 
Gall-fly unknown. On May 18th I found at the bottom of the 
jar, in which a number of these galls had been placed in the preceding 
autumn, 10 or 12 orange-colored Gynipidous larvae dead and dry. Pro- 
