1865.] 355 



tinctive character between G. inanis and C. spongifica; the galls, how- 

 ever, are very different. It is not impossible that we have here not a 

 species, but a phytophagic variety, habitually attacking a different spe- 

 cies of oak, and, owing to the physiologic peculiarities of this species of 

 tree, producing a s-oniewhut different gall. C.futilis and C. papillata 

 (compare above, Nos. 9 and 10) stand probably in the same relation to 

 each other. 



25. C. coelebs 0. S., Proc. etc. I, p. (30, No. 7 ( % ; Q. rubra >. 

 The male (the only sex I know), is remarkably like C. spongifica % , 

 and differs only by its smaller size, its somewhat paler feet, and a 

 less distinct areolet. The gall is very different in shape from the galls 

 C. spongifica and C. inanis. although the principle of its structure is 

 the same, as it contains a single uucleus, kept in position by fibres ra- 

 diating towards the shell. If this gall really occurs on Q. rubra, of 

 which I have but little doubt, it is a remarkable fact that two insects 

 so closely allied as C. inanis and O. coelebs should produce so different 

 galls on the same kind of oak. The females (both sexual and dimor- 

 phous) of C. coelebs remain as yet to be discovered. 



26. C. ilicifoli^e Bassett, Proc. etc. Ill, p. 682 ( % 9; Q. ilici/oiia ). 

 The gall is spindle-shaped, like the preceding, but much larger and 

 broader in the middle. 



27. C. sixgularis Bassett, Proc. etc. II, p. 326 (£ 9; Q. rubra). 

 Compare also Walsh, 1. c. p. 484. Whether 0. nubilipennis Harris 

 (Ins. etc. p. 548, 3d edit.) is really this insect, seems very doubtful, as 

 I do not perceive in my specimens any vestige of a " smoky cloud on 

 the tip of its wings," which determined the choice of the name of the 

 species. Nor do I think that the description " galls of the size and 

 color of grapes" applies to the gall of G. nubilipennis better than to any 

 other gall. The gall described by Dr. Fitch as that of C. nubilipennis 

 is certainly identical with Mr. Bassett's gall, but whether it is identical 

 with Mr. Harris' gall, is another question; it is equally uncertain whe- 

 ther the gall-fly which Dr. Fitch calls C. nubilipennis, really belongs to 

 his gall, as, according to his own statement, it was found on the ground 

 among fallen oak-leaves. Under such circumstances, I would propose 

 to retain Mr. Bassett's name for the gall and fly described by him. 



28. C. Osten Sackenii Bassett, Proc. etc. II, p. 327 ( S ? ; Q. 

 ilicifoliei). As Mr. Bassett observes, this gall is very like a gall on Q. 

 coccinea, which I described (Proc. etc. I, p. 256). Nevertheless, I 

 would hesitate to unite them before convincing myself of the identity 

 of the gall-flies. I do not know the gall-fly of my gall ; the gall and 

 gall-fly of 0. Sackenii I owe to the liberality of Mr. Bassett. 



