CECIDOMYIIDAE 



459 



Cecidomyiids. The Xorth American I)ij)losis resinicola lives in 

 the resin exuded as the results of the attacks of a caterpillar. 

 The larva burrows in the semi-liqviid resin, and, according to 

 Osten Sacken,^ is probably amphipneustic. Cecidomyiid larvae 

 are short maggots, narrowed at the two ends, with a very small 

 head, and between this and the first thoracic segment (this bears a 

 stigma), a small supplementary segment ; the total number of seg- 

 ments is thirteen, besides the head; there are eight pairs of stigmata 



Fig. 219. — Cecidomyia (Diplosis) luxi. 

 Britain. A, Larva, magnified ; B, 

 pupa ; C, imago ; D, portion of an- 

 tenna. (After Laboulbene.) 



Fig. 220. — One segment of an- 

 tenna of Xylodiplosis sp. ; a. 

 Tip of one segment ; b, base of 

 anotlier. (After Janet.) 



on the posterior part of the body. Brauer defines the Cecido- 

 myiid larva thus, " peripneustic, with nine pairs of stigmata, the 

 first on the second segment behind the head ; two to nine on fifth 

 to twelfth segments; body as a whole fourteen - segmented 

 without a fully-formed head." The most remarkable peculiarity 

 of Cecidomyiid larvae is that those of many species possess a 

 pecuHar organ — called breast-bone, sternal spatula, or anchor- 

 process — projecting from the back of the lower face of the pro- 

 thoracic segment. The use of so peculiar a structure has been 

 much discussed. According to Giard,^ in addition to the pai-t 

 ' Tr. Amer. ent. Soc. iii. 1871, p. 345. ^ Bull. Soc. eni. France, 1893, p. Ixxx. 



