CECIDOMYIA. 201 



a jagged fence round the gall. Such galls are generally empty, 

 the larvae having perhaps gone under ground, although one of the 

 specimens which I brought home was inclosed in a delicate cocoon 

 inside of the gall. 



The larva is reddish, and has the usual breast-bone with a deep 

 excision in the middle anteriorly ; the two lobes thus formed are 

 rounded. 



These galls, as I remarked before, protrude symmetrically on 

 both sides of the leaf. On other kinds of oak, especially the cpier- 

 eitron oak (Q. tinctoria), I found similar galls, but on the upper 

 side of the leaf only, without the corresponding excrescence on the 

 under side. Those I brought home were abandoned by their larvae, 

 which went under ground. Thus I am very uncertain about the 

 identity of both galls, as well as about the habits of the insects. 

 As all these galls were found with larva? late in autumn, it is evi- 

 dent that the fly escapes very early in the spring. 



22. C. poculum, n. sp. The so-called oak spangles (Fitch, Rep., 

 vol. II, No. 40), small, circular, somewhat saucer-shaped scales, 

 from 0.1 to 0.2 in diameter, reddish or purplish, covered with a 

 white efflorescence, attached to the leaf by a short pedicel, common 

 in autumn on different kinds of oaks, are generally found empty. 

 In the beginning of August I found a similar gall, yet succulent 

 and greenish, on the post oak (Q. obtusiloba), and inside of it a 

 small whitish larva having all the appearance of the larva of a 

 Cecidomyia, although, on account of its minuteness, I did not suc- 

 ceed in discovering the breast-bone. 



Dr. Fitch is in error when he states that these galls are " per- 

 fectly the same" as those noticed by Westwood, Introd., II, p. 

 130. The European galls of this kind are pilose externally, as 

 stated by "Westwood and figured by Reaumur (Mem., vol. Ill, Tab. 

 XL, f. 13); the American ones, at least those which came under 

 my notice, are smooth. 



23. Lasioptera vilis O. S. Swelling of the stem and leafstalks 

 of the wild grape. This irregular succulent swelling, which be- 

 comes red on its stouter and riper portions, extends not only along 

 the stem and leafstalks, but also invades the leaf-ribs. It contains 

 round hollows of about 0.1 in diameter with an orange-yellow 

 larva in each. Some of the hollows are often abandoned by their 

 inmates and invaded by numerous Tltrips. Having brought this 



