D4. MISC. PUBLICATION 305, U. S. DEPT. OF AGRICULTURE 
Society of Natural History; paratype in the Museum of Comparative 
Zoology. 
Type locality —Southwest Harbor, Maine. 
Distribution.—Minnesota and Newfoundland to Indiana and Con- 
necticut. June 19 (Lyme, Conn.) to September 9 (Southport, 
Maine). In the United States National Museum, eight females, four 
males, 
ATYLOTUS THORACICUS (Hine), new combination 
(Fig. 7, C) 
Tabanus thoracicus Hine, Canad. Ent. 32: 248, 1900. 
Small; pleura gray; pale hair of sides of abdomen bright yellow; no frontal 
calli. 
Female.—Length 9-11 mm. Eye pilose. Frons pale yellowish, with yellow 
hair, three to four times as high as wide, with parallel sides and no denuded 
basal or median callus; subcallus pale brownish yellow. First two antennal 
segments yellow, with black hair, the second with a pronounced dorsal process ; 
third segment orange, the basal portion stout, with a prominent, obtuse, dorsal 
angle and no dorsal excision; annulate portion stout, indistinctly four-seg- 
mented, slightly shorter than width of basal portion. Clypeus and genae gray, 
with white hair. Second palpal segment whitish, distinctly swollen basally but 
tapering to a slender apex; hair erect, a mixture of black and white. Proboscis 
yellow, not much longer than palpus. ; 
Thorax gray, the dorsum with mostly yellow hair, pleura and sternum with 
whitish hair. Wing hyaline, with yellow veins and usually without a stump 
from vein Rs: Coxae gray; rest of legs yellow, with mostly black hair, the 
femora basally often gray. 
Abdomen above dull yellow, with yellow hair, the sides of first few segments 
paler yellow; venter yellow, the extreme base often somewhat gray. 
Male.—Eye pilose, the areas of large and small facets rather distinctly dif- 
ferentiated. Postorbital hairs near vertex intensely yellow. Second palpal 
segment moderately stout. Coloration of whole body essentially as in female, 
but genae usually yellower and abdomen grayer midventrally. 
Type.—A lectotype female, United States National Museum No. 
5340, selected and herein designated from a male and a female cotype 
in the United States National Museum and a female cotype at the 
Ohio State University. 
Type locality —Oswego, N. Y. 
Distribution—Wisconsin to Ontario and Delaware. June 8 
(North Mountain, Pa.) to August 1 (Oswego, N. Y.). In the United 
States National Museum, two females, five males. 
The Genus LEUCOTABANUS Lutz 
Leucotabanus Lutz, Brazil-Medico 27 (45): 487, 1913. (Genotype, Tabanus 
leucaspis Wiedemann. ) 
Generic characters—Small to medium sized; eye bare or sparsely pilose; 
frons of female very narrow, with a small basal callus forming a swelling at 
base of a long, slender, median callus; ocellar tubercle present; third antennal 
segment with five divisions, the first with a distinct dorsal angle; thorax 
usually with dense white hair; abdomen brownish to black, with white bands, 
apex distinctly compressed. 
Key to the Nearctic Species of Leucotabanus 
1. Length 10-12 mm; antenna orange, femora reddish____annulatus (Say), p. 25. 
Length 15-18 mm; antenna and femora black-_-_ambiguus, new species, p. 26. 
