REPORT OF THE STATE ENTO:\rOLOGTST I912 I2y 



APPENDIX 



A STUDY OF GALL MIDGES 



The gall midges comprise an immense family of small flies or 

 Diptera known as the Itonididae or Cecidomyiidae, represented 

 in America by about 900 known species, approximately half hav- 

 ing been reared from the deformities or galls they produce or 

 matter upon which they live. The species referable to this family 

 may be recognized by the tibiae being unarmed apically, the coxae 

 not produced, and the wings usually with but three or four long 

 veins and no crossveins. Extreme forms may have six or seven 

 long veins and one crossvein or, as a result of reduction, the wing 

 veins may be nearly absent. 



There are in this family a number of important insect pests, 

 such as the Hessian fly, Phytophaga destructor Say ; 

 the wheat midge, Itonida tritici Felt ; the pear midge, 

 Contarinia pyrivora Riley ; the clover midge, D a s y - 

 neura leguminicola Lintn. ; the violet gall midge, Phy- 

 tophaga violicola Coq. ; the rose midge, Dasyneura 

 rhodophaga Coq. ; and the grape blossom midge, Contar- 

 inia j o h n s o n i Sling. In addition to these there are a num- 

 ber of other potentially injurious midges, not to mention European 

 species, which may become established in this country at almost 

 any time and cause serious losses in somewhat the same way as 

 did the Hessian fly in earlier years. 



Our knowledge of American gall midges was in a very unsatis- 

 factory condition in 1895. The following discussion of the Les- 

 tremiinae and Heteropezinae comprises a systematic descriptive 

 account of these groups. 



LESTREMIINAE 

 The members of this subfamily are almost invariably medium to 

 small, dark brown or black species, easily distinguished from all 

 other Itonididae by the five"" tarsal segments, the metatarsus being 

 longer than the following segment, and the presence of the fourth 

 long vein, which latter may be either forked as in Lestremia 

 or simple and obsolescent as in Campylomyza. The antennae 

 may be moderate as in Lestremia and Campylomyza or extremely 

 short as in Tritozyga and Microcerata. The circumfili, so 

 characteristic of the higher groups, are entirely wanting in this 



