64 THE CANADIAN ENTOMOLOGIST 



 — Tibiae black; wings usually infuscated, more distinctly so basally, veins 

 black; abdomen ovate except in alticola, the dorsal spots large, separ- 

 ated by a linear space; fore tibia without a median posterior bristle 

 except in alticola 23 . 



23. Eyes separated by more than twice the width across posterior ocelli ; hind 



femur with long bristly hairs on basal half of posteroventral surface... 24. 



— Eyes separated by less than twice the width across posterior ocelli 25. 



24. Fifth abdominal sternite with a chitinous protuberance near apex on each 



side of posterior excavation; mid femur without strong bristles at 

 base on posteroventral surface acuticornis Malloch. 



— Fifth abdominal sternite without such protuberance; mid femur with 



strong bristles on basal half of posteroventral 



surface surda Zetterstedt?. 



25. Abdomen cylindrical, slightly tapered apically; hind femur with long 



bristly hairs on basal half of posteroventral surface; eyes separated by 



more than width across posterior ocelli alticola Malloch. 



 — Abdomen ovate; hind femur without long bristly hairs on posteroventral 

 surface ; eyes separated by less than width across posterior ocelli 26. 



26. Fifth abdominal sternite with sparse setulose hairs laterad and distad of 



base of posterior excision; abdominal dorsal spots separated by a 

 linear space ma gni punctata Malloch . 



— Fifth abdominal sternite with very dense short setulae laterad and distad 



of base of posterior excavation; the dorsal abdominal spots on third 

 and fourth tergites rather widely separated, much more so than those 

 on second imitatrix Malloch. 



27. Thorax when viewed from behind with the anterior half of disc brownish 



black, the posterior half densely gray pruinescent; abdominal dorsal 

 spots narrow, elongate, sometimes linear; mid tibia without an antero- 

 dorsal bristle; hind femur unarmed on posteroventral 



surface clivicola Malloch. 



• — Thorax deep black w^hen viewed from behind, only the posterior margin 

 grayish pruinescent; abdominal dorsal spots large and broad; mid 

 tibia with one or more anterodorsal bristles; hind femur with some 

 short, stout bristles on median third of posteroventral 

 surface gihsoni Malloch 



Limnophora Robineau-Desvoidy. 

 Key to Species. 



1. Fifth abdominal sternite in male much longer than fourth; male hind 



femur incrassated at base and apex incrassata Malloch. 



— Fifth abdominal sternite in male not longer than fourth; femora normal. .2. 



2. Eyes of male narrowly separated, the frons not wider than third antennal 



segment; first posterior cell of w^ng much narrowed 



apically narona Walker. 



— Eyes of male separated by more than width of third antennal segment; 



first posterior cell of w^ing almost imperceptibly narrowed apically... 3, 



3. Female with an anterodorsal bristle on mid tibia groenlandica Malloch. 



 — Female without an anterodorsal bristle on mid tibia discreta Stein. 



