AMERICAN DIPTERA. 243 



some differences which might render the recognition doubtful. 

 The antennae are not as long as the head and thorax combined, 

 but considerably" shorter, and the third segment is at least 

 one-half longer than the first ; the third segment has two pro- 

 cesses like the fourth segment. There are but two segments 

 in the style, as in Ceraturgus. 



Type. — Myelaphus melas Bigot. 



The above description has been taken almost bodily from 

 Dr. Williston's paper above cited. With material now in col- 

 lections it cannot be bettered. I have seen the specimens of 

 melas and rufus used by Dr. Williston, and many specimens 

 of lobicornis. When more collecting has been done, I believe 

 that interesting facts in variation will be discovered. 



SYNOPSIS OF SPECIES. 



1. Face, in profile, wholly without a protuberance near the middle; 



head and thorax black; legs and abdomen for the most 



part yellowish- red lobicornis. 



Face, in profile, with a moderately large obtuse tubercle 2. 



2. Wholly black species melas. 



Yellowish-red species rufus. 



Myelaphus lobicornis. 



Ceraturgus lobicornis Osten Sacken, West. Dipt., 287, 1877. 



Ceraturgus lobicornis Brauer, Wien. Ent. Zeit., II, 56. 



Myelaphus lobicornis Williston, Trans. Am. Ent. Soc. XI, 7, 

 XII, 53; XIII, 288 (additional notes). 

 cj 9 • — Length 10-12 mm. — Head and thorax wholly black; coxae, 

 trochanters, more or less of the base of the four fore femora, tips of 

 the tarsi narrow, lateral margins of the abdomen black or blackish; 

 legs and abdomen yellowish-red. Wings in the male tinged with 

 brown, darker, sometimes dark brown, in front toward the base; in 

 the female the basal half yellowish. Face without gibbosity, most 

 prominent above where there is a slight protuberance upon which are 

 borne the antennae. 



Face for most part bare, polished black, often with a golden pruinose 

 stripe on each side above the golden mystax. Antennae wholly black; 

 front polished. Thorax with short, closely appressed golden pile, not 

 dense on the dorsum above, but quite so on the lateral margins, pro- 

 notum, meso- and hypopleurae and scutellum. A stripe from the base 

 of the wings to the middle coxae bare, polished. Halteres yellow 

 usually with a pinkish tinge. Abdomen polished, with sparse micro- 

 scopic pile; genitalia red with white pile ; the extreme base and the 



TRANS. AM. ENT. SOC, XXXV. JULY, 1909. 



