8 PROCEEDINGS OF THE NATIONAL MUSEUM vol.79 



27. Abdomen pollinose or subpollinose to hind margins of inter- 



mediate segments 28 



Abdomen with alternating white and black cross bands on last 

 three segments; inner forceps narrow at base, uniform in 

 width almost to the deeply incised apex, in profile thicker than 

 usual and strongly bowed (Canal Zone)— tricolor van der Wulp (p. 42> 



28. Inner genital forceps very slender and but feebly keeled near 



base behind; outer fox-ceps nearly equal the length of inner 

 ones (North, Central, and South America). 



intermedia, new species (p. 41) 

 Inner forceps of ordinary width and sharply keeled behind on 

 basal two-thirds; outer forceps about one-half the length of 

 inner pair, triangular (Texas) imitator, new species (p. 39) 



1. Scutellum with three lateral bristles 3 



Scutellum with only two lateral bristles 2 



2. Parafrontals and face plumbeous ; abdominal hairs erect ; third 



antennal joint three times the length of second (California, 



New Mexico) antennalis Coquillett (p. 10> 



Parafrontals and face covered with thick brassy or yellowish 

 gray pollen ; abdominal hairs depressed ; third antennal joint 

 one and one-half times as long as second (British Columbia). 



intonsa, new species (p. 28) 



3. Prosternum with only fine hairs at sides 4 



Prosteruum bearing one or more bristles on either side ; abdo- 

 men largely reddish (North America, widespread). 



deilephilae Osten Sacken (p. 33) 



4. Apical joint of fore tarsi ordinary 8 



Apical joint of fore tarsi elongated or distinctly bulged on sides 5 



5. Tibiae and femora black & 



Tibiae broadly red at middle, femora largely so ; parafacial 



almost linear below ; last joint of fore tarsi distinctly shorter 

 than the combined length of two preceding ones (Brazil). 



bicolor, new species (p. 46) 



6. Abdomen with well-defined pollinose cross bands, segments 2 



and 3 shining on broad apices T 



Pollen on abdomen not in defined cross bands, the intermediate 

 segments at least subpollinose to the hind margins ; last joint 

 of front tarsi hardly longer than normal ; the black thoracic 

 stripes separated and distinct on entire length (Georgia, 

 Cuba) okefenokeensis Smith (p. 52) 



7. Apical joint of fore tarsi greatly elongated approximating or 



exceeding the combined length of two preceding joints ; third 

 antennal joint black; abdomen gray pollinose (Mexico, Central 



and South America) pinguis Frbricius (p. 40). 



Apical joint of fore tarsi much shorter than two preceding 

 joints; antennae entirely reddish; pollen on abdomen tinged 

 with yellow (Mexico, Central and South America). 



xanthocera Wiedemann (p. 44) 



