154 MISC. PUBLICATION 305, U. 8S. DEPT. OF AGRICULTURE 
MNstribution—British Columbia to Arizona, Colorado, and Minne- 
sota. June 15 (Kaslo, British Columbia) to September 3 (Mount 
Rainier, Wash.). In United States National Museum, 189 females. 
TABANUS RHOMBICUS variety RUPESTRIS McDunnough 
Tabanus rupestris McDunnough, Canad. Ent. 53: 143-144, 1921; Philip, Canad. 
Ent. 68: 153, 1936. 
This variety differs from typical specimens of rhombicus in the presence of a 
considerable amount of orange on the side of the abdomen and the venter. 
Structurally the two forms appear identical. 
Type.—aA female in the Canadian National Collection. Paratypes, 
two females in the Canadian National Collection. 
Type locality —Gallatin County, Mont. 
Distribution.—Idaho and Montana to Colorado. July 5 (Yellow- 
stone Park, Wyo.) to August 9 (Ravalli County, Mont.). In the 
United States National Museum, 14 females, 3 males. 
Tabanus osburni Hine is based upon specimens that are somewhat 
blacker and more shiny in appearance than typical rhombicus, with 
the abdominal triangles less distinct and the costal cell slightly 
brownish. It seems to occur in the more northern part of the range. 
This shght color difference and the intergradation between the two 
forms makes its recognition as-a variety of doubtful value. The type 
of Hybomitra solow Enderlein was examined by the writer and 
proved to be 7’. rhombicus, typical form. Philip has shown 7’. centron 
Marten to be a synonym of rhombicus. 
Tabanus rhombicus is of considerable economic importance in the 
northern Rockies, where it occurs in abundance. 
TABANUS FRETUS, new species 
(Fig. 74, C) 
Small; dark brownish black, with three rows of pale spots on abdomen; 
pleura with dense white hair; wing hyaline; eye pilose; subcallus denuded. 
Female.—Length 12 mm. Hye densely pilose, purple, with four green bands. 
Frons gray tinged with yellow brown, with black hair, three times as high as 
basal width, somewhat widened above; basal callus shiny dark chestnut brown, 
convex, nearly round, not quite touching eyes; median callus black, rather 
small; ocellar tubercle orange brown, protuberant; Subcallus denuded except 
along lateral margins and around antennae, concolorous with basal callus. 
First two antennal segments yellow brown, with black hair; third with basal 
portion orange, annulate portion black; dorsal angle distinct, the excision 
shallow. Clypeus and genae white, with white hair. Palpus creamy white, 
with white and some scattered black hair; second segment stout basally. 
Proboscis rather short, the labellae large. 
Mesonotum dark brown, with five indistinct paler stripes in usual pattern; 
prescutal lobe yellow brown. Pleura, sternum, and coxae light gray, with white 
hair, the upper mesopleurite tinged with reddish, with a little black hair. Wing 
hyaline, the venation normal. Legs yellowish brown, the middle and hind 
femora grayish on basal half and fore tarsus dark brown; hind tibial fringe 
black. 
Abdomen above blackish tinged with orange laterally; a median row of 
small pale-yellowish spots on tergites 1-5 and oblique sublateral spots on 
tergites 2-5, that on tergite 2 largest, reaching to anterior margin; venter 
uniformly light yellow orange. 
Male.—Eye densely pilose, the large and small facets not sharply dif- 
ferentiated; frontal triangle light gray; clypeus and genae entirely white, with 
white hair; palpus light yellow brown, the second segment cylindrical, about 
twice as long as thick, with blunt apex. Dorsum of thorax blacker than in 
female, the lines not evident; pleura with pile entirely white; legs slightly 
