June, I9I7-] TOWNSEND : HeaD AND ThROAT BoTS. 101 



cotiesi C. & Y., in the Sierra ]\Iadre of western Chihuahua, near 

 Meadow Valley, at about 7,000 feet, which were almost certainly 

 pratti. They occurred principally in the nares and pharynx. No 

 pockets in the throat were noted. It was common for a dozen or two 

 to issue from the nostrils and mouth of the host soon after death. 

 Unfortunately none of them was sufficiently mature for the rearing 

 of the fly. The percentage of infestation of the host was very large. 

 Messrs. Nelson and Goldman, of the Biological Survey, were in the 

 same country at this time and noted the same hots commonly in the 

 same host. 



On several occasions I saw what I believe to have been the female 

 flies of this species passing with incredible swiftness up and down 

 over the stream in the head of the Rio Piedras Verdes canyon, near 

 Meadow Valley. They flew high overhead, entirely out of reach, and 

 were never seen to alight. About the only impression left by them 

 on the eye was that of a blur or streak of orange or reddish and 

 black, the red dominant. So far as could be judged from these 

 fleeting glimpses, the flies were largely of a deep orange-red or rich 

 red-brown, and seemed to be strongly piliferous. They appeared to 

 be of good size, not heavy of body but rather long of legs, and very 

 strong of wing. They were probably females looking for hosts. The 

 females are somewhat larger than the males in this genus, and the 

 impression of rather long legs was probably due to the extension 

 of the legs below in flight. The pilosity of the extended femora, 

 mostly black, helped to exaggerate the size. The males of the genus 

 are usually met with only on bare mountain tops. 



1903. One immature third-stage larva, taken by Mr. H. S. Barber 

 from the nose of a blacktail deer at Bair's Ranch, on Redwood Creek, 

 Humboldt County, California, June 17, is pratti. 



1910. Eight third-stage larvae were taken by Mr. F. C. Pratt, of 

 the Bureau of Entomology, from nasal passages of Odocoileus 

 tc.vaniis Mearns at Sabinal, Texas, in November. Three of these 

 pupated, and two of the pupae later disclosed male flies. From this 

 material Dr. Hunter, in 1915, described the fly, third-stage larva and 

 puparium under the name pratti (Proc. Ent. Soc. Wash., XVH, pp. 

 169-173, pi. XVI). Examination of the genitalia of the two speci- 

 mens of the fly labeled allotype and holotype, described respectively 

 as male and female, shows that both are males. The width of vertex 



