320 



Key to Species 



1. Halteres with black knob 2 



— Halteres with yellow knob 5 



2. Mesonotuni opaque gray, with central brown vitta ; fore femora with 



10-12 spines on apical half ; mid and hind femora with but 1 dis- 

 tinct spine ; claws large, subequal, toothed near base ; last tarsal 

 joint unarmed 1. illinoensis. 



— Mesonotum black, without central vitta 3 



3. Fore femora with one spine at middle, the other femora bare 



2. scahra. 



— All femora with spines 4 



4. Hind tibiae entirely black ; third vein to about five sixths the wing- 



length 3. tibialis. 



— Hind tibise yellow, their apices blackened ; third vein to nine tenths 



the wing-length 4. suhasiicr. 



5. Only one pair of femora, fore or hind, with spines G 



— All femora spinose or only fore femora bare 7 



6. Fore femora with 1 spine at middle, the other femora bare 



2. scahra. 



— Hind femora spinose, the other femora bare ; legs yellow, apices of 



femora, of tibia', of first 3 tarsal joints and whole of last 2 tarsal 

 joints blackish brown ; claws of fore and mid tarsi subequal, those 

 of hind pair very unequal in length ; hind femora with 2 spines . . 

 5. curriei. 



7. Legs yellow, middle and extreme apices of hind femora, the hind 



tibife except a small portion beyond middle, the apices of fore and 

 mid tibiae and bases of latter, and last 3 tarsal joints blackened ; 

 middle portion of the thickened last tarsal joint of fore legs white ; 

 claws of fore tarsi equal, those of mid and hind pairs very unequal 

 in length ; all femora with 1 spine 6. nehitlosa. 



— Mid and hind femora with at least 2-3 ventral spines 8 



8. Mesonotum densely gray pollinose, without distinct brown spots or 



vittffi; legs almost entirely blackish brown 7. sc]iwa7'zi. 



— Mesonotum either glossy black, or opaque gray with distinct In-own 



spots on disc 9 



9. Mesonotum glossy black ; wings with a large black spot . . 8. nnhifera. 



— Mesonotum opaque gray ; wings clear 10 



10. Apices of fore femora yellow 9. longipennis. 



— Apices of fore femora blackened 10. slossowv. 



I. Palpomyia illinoensis Malloch 



Palpomyia illinoisensis Mallocli, Bull. 111. State L.ab. Nat. Hist., Vol. 10, Art. 4 

 (1914), p. 219. 



The type specimen is from Algonquin, 111. 



I have seen a single specimen from Ithaca, N. Y., which does not 

 differ from the type except in having the spines on fore femora in a 



