352 



I do not know the larvae of Arthropcas, which may not conform 

 to the characters here given for the family. 



FAMILY CHARACTERS 



Larva. — In general appearance similar to Xylophagidae. Head 

 rather large, the exposed portion in the form of a strongly chitinized 

 cone, from the small apical portion of which are protruded the man- 

 dibulate parts. Thoracic segments each with a pair of round oval 

 chitinized plates under the skin. Apical abdominal segment obliquely 

 truncated, the lower posterior margin with a pair of projecting proc- 

 esses ; posterior spiracles widely separated, situated above middle of 

 apical plate, anterior pair on sides of first thoracic segment. 



Pupa. — Head without projecting thorns; antennal sheaths ele- 

 vated, the annulation indistinct. Abdomen with comparatively weak 

 armature, which becomes stronger apically ; postspiracular areas each 

 with 2 bristles ; apical segment with a fan-shaped armature of 5-6 

 bristles on each side ; apical protuberances small. 



Imago. — Xcvx large, robust species, of a variable brownish or 

 testaceous color. Distinguishable from the Leptidae, in which family 

 it has been placed by some authors, by the elongated and annulated 

 third antennal joint. The males of both genera may be separated 

 from Xylophagidae bv the contiguous eyes ; both sexes of Coenomyia, 

 by the spines on scutellum ; and both genera, by the characters given 

 in key to imagines of Brachycera. 



HABITS OF I,ARVAK 



The larva of Coenomyia pallida is usually found in the ground, 

 those that I have before me being obtained in fields some distance from 

 any timber. They are, however, sometimes found in decaying wood. 

 They are predaceous upon insect larvae. A specimen found in a field 

 near Chicago fed upon white-grubs. The larvae are very sluggish, 

 moving very slowly through the earth, and are almost incapable of 

 making progress upon a smooth surface. I know of no parasites of 

 the larvae. 



HABITS OF IMAGINES 



Coenomyia pallida is usually found near streams and more par- 

 ticularly among undergrowth or trees, and is rather sluggish. The 

 food consists of fluid matter or nectar of flowers. 



