354 ERNEST A. BACK. 



2. Wings altogether blackish or brown 3. 



Wings more or less hyaline, at least not as above 4. 



3. Wings and abdomen black; thorax brownish, legs yellowish. 



platyptera. 



Wings brown or blackish, abdomen and legs yellowish (Mexican 



and southwestern species) sallei. 



4. Abdomen reddish; last two segments and anterior margins of the 



other segments and venter black (Texan species). 



hypomelas. 

 Abdomen reddish or black, but never with the above combina- 

 tion of color 5. 



5. Bristles of pronotum black 6. 



Bristles of pronotum yellowish 7. 



6. Hair and bristles of coxae rarely wholly, always partly, black; 



common rich reddish-brown, sometimes paler, species of 

 the northern Atlantic States, with stout abdomen with 

 black and pale golden spots on the sides of segments 2-5 



or 6 umbrinus. 



Hair and bristles of coxae always pale; abdomen of male long, 

 slender, black; posterior angles of segments 2-5 broadly 

 white pruinose; female with two very narrow dark median 

 lines on dorsum, abdomen reddish-yellow with segments 

 2-5 showing on sides a black and yellow pruinose area. 



discolor. 



7. Length 30-33 mm.; see description of bigoti. 



Length 15-17 mm.; palpi black, abdomen almost wholly pruinose 



without black spots (southwestern species) perplexa. 



Length 16-25 mm.; palpi reddish-yellow; abdomen with black 



spots along the sides symmacha, angustipennis, 



rufescense and sometimes bilineata. 



8. Abdomen long, cylindrical; in the male coarctate, the greatest 



constriction between the second and third segments. 



tern at a. 

 Abdomen flattened, not at all coarctate in male 9. 



9. Length 19-23 mm.; the two median narrow stripes not merging 



into red anteriorly (Cuban and Florida species).. bilineata. 



Length 14-17 mm.; the median dorsal stripe not geminate, but 



merging into red anteriorly winthemi. 



Deromyia angustipennis. 



Diogmites angustipennis Loew, Cent., VII, 41, 1866. 



Deromyia angustipennis Williston, Trans. Am. Ent. Soc, XI, 25, 



1884 (note). 

 Deromyia angustipennis Jones, Trans. Am. Ent. Soc, XXXIII, 

 280, 1907 (locality note). 

 $ 9- — Length 18-20 mm. — More grayish than the other species; 

 head and thorax dull yellowish-gray pruinose, the thoracic stripes dis- 



