DIPTERA 



849 



rest lie parallel upon the abdomen ; the axillary 

 excision is prominent, but the posterior lobe of 

 the wing is small (Fig. iioi); the alulets are 

 minute. 



The radial sector is two-branched; veins 

 Ml and M2 either coalesce throughout or sep- 

 arate near the margin of the wing ; the medial 

 cross vein is present in some members of the 

 family and absent in others; cells 2d R, M, 

 and ist A are short. 



This family is represented in North Amer- 

 ica by about twenty-five species, and these are 

 usually rare. The larvae live in mushrooms, 

 the puparia are not very different from the 

 larvas in form. 



Fig. 1 1 00.— Leg of P/d- 

 typeza, a, forked 

 hairs of leg greatly- 

 enlarged. 



IIOI. — Wing of Platypeza. 



Family PIPUNCULID^ 

 The Big-eyed Flies 



The members of this family are small flies with very large heads 

 composed almost entirely of eyes (Fig. 1102). The 

 head is nearly spherical and broader than the thorax. 

 The antennse are small, short, three-jointed, with a 

 dorsalarista. The ocelli are present. Theabdomenis 

 somewhat elongate with the sides nearly parallel. 

 The body is thinly clothed with hair or nearly naked. 

 The wings are much longer than the abdomen, and 

 when at rest they lie parallel to each other upon it. 

 The venation of the wings (Fig. 11 03) closely re- 

 sembles that of the Conopid^. The radial sector is 

 two-branched. Veins R4+5 and Mi +2 approach each 

 other at their tips. Vein M3 coalesces with vein Cui for nearly its 



Fig. II 02.- 



punctdus. 



-Pi- 



