Diy MISC. PUBLICATION 305, U. S. DEPT. OF AGRICULTURE 
characters may be found, and certainly the two forms already named 
show relatively constant color differences from the typical form. 
However, any segregation based on color exhibits considerable struc- 
tural variation and the converse. Until more collecting can be done 
and further study made on the seasonal, climatic, and geographic 
distribution of the forms the writer prefers to place them all under 
the one name, freely admitting that this is not the final solution of the 
problem. 
ATYLOTUS BICOLOR (Wiedemann) 
(Fig. 6, C) 
Tabanus bicolor Wiedemann, Diptera Exotica, pt. 1, p. 96, 1821; Osten Sacken, 
Mem. Boston Soe. Nat. Hist. 2 (pt. 4, No. 4): 460, 1876; Hine, Canad. Ent. 
32: 247, 1900; Ohio State Acad. Sci. Spec. Papers 5: 48, 1903; Stone, Ann. 
Ent. Soc. Amer. 238: 296-297, 1930. 
Tabanus fulvescens Walker, List of the Specimens of Dipterous Insects in the 
Collection of the British Museum, pt. 1, p. 171, 1848; Osten Sacken, Smithsn. 
Misc. Collect. No. 270, pp. 62, 229, 1878. 
Tabanus ruficeps Macquart, Diptéres exotiques nouveaux ou peu connus, sup. 5, 
p. 55, 1855; Osten Sacken, Smithsn. Misc. Collect. No. 270, p. 62, 1878. 
Atylotus bicolor Osten Sacken, Smithsn. Misc. Collect. No. 270, p. 62, 1878. 
Small; yellow; abdomen above often darkened medianly; eye pilose; no 
frontal calli. a 
Female—tLength 10-13 mm. Eye finely pilose, with a narrow, diagonal, 
dark line from lewer inner angle, often showing even in dried specimens. Whole 
body orange yellow, the mesonotum, and a broad median line on abdomen which 
widens posteriorly, somewhat darker and grayer. Head with yellow hair. 
Frons about three times as high as wide, with parallel sides; no ocellar tubercle 
or basal or median callus. Antenna uniformly yellow; third segment short and 
stout, width of basal portion about equal to length, with no dorsal excision, 
but dorsal angle prominent: annulate portion slightiy shorter than basal por- 
tion. Second palpal segment short, very stout at base, tapering to an acute 
apex: hair long, yellow, with a few scattered black ones. Proboscis yellow, only 
slightly longer than palpus. 
Wing hyaline, the veins yellow; costal cell and base of wing slightly tinged 
with yellow: venation normal. Legs yellow, the tarsi sometimes slightly 
darker; no hind tibial fringe, although there are some seattered dark hairs on 
tibiae. 
Male—Eye not flattened above, the area of large facets rather sharply 
differentiated from the area of small facets, the latter extending around top of 
eye in a rather broad band. Second palpal segment stout, with blunt apex. 
Coloration of body as in female. 
Type.—Male, collection unknown, perhaps Vienna Museum. 
Type locality —North America. 
Distribution.—Alberta to New Mexico and east to Ontario, Maine, 
and the District of Columbia. June 30 (McLean, N. Y.) to August 
28 (Block Island, R. I.). In the United States National Museum, 
12 females, 7 males. 
ATYLOTUS OHIOENSIS (Hine), new combination 
(Hig. 77,2 Ab) 
Tabanus pruinosus Hine, Canad. Ent. 32: 248, 1900. (Preoecupied by Tabanus 
pruinosus Bigot.) 
Tabanus ohioensis Hine, Canad. Ent. 33: 28, 1901; Ohio State Acad. Sci. Spec. 
Papers 5: 53, 19038. 
Small; almost uniformly gray or brownish black, the venter and at least 
base of femora gray. 
Female.—Length 8.5-10 mm. Eye with rather dense, yellowish pile. Frons, 
Subcallus, clypeus, and genae pale yellowish, somewhat grayed below. Frons 
