NORTH AMERICAN DIPTERA. G5 



Females. 



1. — Dorsum of thorax with a mane-like crest 2. 



Dorsum of thorax without such crest 3. 



2. — Tibise and tarsi yellowish red; abdominal segments broadly poUinose on the 



margin latriincii us. 



Abdominal segments narrowly poUinose on the hind naargins.....JHbatus. 



3. — Three sub-maiginal cells aiioisisiliis. 



Two sub-niarginal cells ^ 4. 



4. — Face in profile moderately concave below the antennse; femora in part red; 

 abdomen black, the second and third segments with a large white spot on 



each side behind second sub-marginal cell long iRteralis. 



Face with a short deeo concavity 5. 



5. — Mystax straw-yellow; abdomen chiefly black; furcation of third vein before 



the base of second posterior cell aestdiaiiS. 



Mystax white or black fi. 



6. — Abdomen nearly uniformly white poUinose ; furcation of third vein beyond 

 the base of the second posterior cell; tibise yellow with black tip; large 



species leucocomiis. 



Abdomen with distinct black markings 7. 



7. — Segments of abdomen with a median black triangle siinilis. 



Segments of abdomen black with a poUinose margin 8. 



8. — The strong facial gibbosity in large part clothed with black bristles ; abdomen 



with the lateral borders and hind margin poUinose ISastardii. 



Head wholly clothed with white, 3-6 abdominal segments each with two large 

 black spots f'urax. 



Additional species from the United States: 



Erax albib9,rbis Macquart, Dipt. Exot. i, 2, 118, 26. — N. Am. 



E. apicalis Wiedemann, Dipt. Exot. i, 119, 16 {Asilus) ; Auss. Zw. Ins. i, 443, 



28.— N. Am. 

 E. completus Macquart, Dipt. Exot. i, 2, 117, 23; tab. ix, fig. 9.— N. Am. 

 E. macrolabis Wiedemann, Auss. Zw. Ins. i, 458, 51 {Asilus). — Ky. 

 E. niger Wiedemann, Dipt'. Exot. i, 196, 26; Auss. Zw. Ins. i, 460, 54 (Asilus). 



— N. Am. 

 E. notabilis Macquart, Dipt. Exot. i, 2, 110, 6; tab. ix. fig. 8.— Am. 

 E. pogonias Wiedemann, Dipt. Exot. i, 198, 29; Auss. Zw. Ins. i,460, 54 (Asilus). 

 — N. Am. 



Dasypogon barbatu.s Fabricius, System Antl. 169, 22. 

 E. vicinus Macquart, Dipt. Exot. ler. Suppl. 85, 36. — Texas. 

 E. stylatus Fabricius, Wiedemann, Auss. Zw. Ins. i, 462, 57, and 

 E. macularis Wiedemann, 1. c. i, 447, 33, South American species, are referred 



to North America by v. d. Wulp, Tijdschr. voor Ent. xxv, 112. 

 I have spared no labor in endeavoring to identify my specimens with 

 the above species and the long list from Mexico, but with poor results. 



Erax tagax n. sp. 



% . — Length 25-28 mm. — Face deeply yellowish gray poUinose, bare above and 

 on the sides, on the gibbosity with white hair interspersed with black bristles, a 

 row of the latter extending along the oral margin; the gibbosity arises very sharply 



TRANS. AMEE. ENT. SOC. XII. (13) JANUARY, 1885. 



