2 PROCEEDINGS OF THE NATIONAL, MUSEUM vol.79 



approaches the letter H in shape. Contrary to the condition de- 

 scribed as occurring in Protostrongylus rufescens, the proximal part 

 of this structure, while not so deeply pigmented as the distal part, 

 has a distinct yellowish-brown coloration, which makes it quite 

 noticeable in cleared specimens. This part of the telamon is 58/x 

 long. The ventral part of the telamon consists of two deeply 

 colored rods, joined at their upper ends and with boot-shaped 

 terminations; the toe of the " boot " is very sharp in some specimens, 

 in others there seems to be a solid chitinous structure from the instep 

 to the toe so that the termination appears to be triangular; this part 

 of the telamon is 96/x, long. The gubernaculum is an arc-shaped 

 structure with its convexity directed toward the head end; there are 

 two sharp prolongations on the dorsal side, and on the ventral side 

 the gubernaculum has the shape of a plate with a convex semi- 

 circular edge. The bursa is short. The ventral rays are united for 

 the greater part of their length. As in other members of the 

 Protostrong3'lidae the other rays are somewhat modified. The ex- 

 terno-dorsals are slender and do not reach the margin of the bursa. 

 The dorsal ray is represented by a solid spherical body, which bears 

 a series of five papillae on its ventral surface. The chitinous arcs 

 described and figured for other members of this genus are present. 



Female : Length uncertain ; width, about IOO/a in the region of the 

 vagina. The body terminates in an acute point. The distance from 

 the anus to the tip of the tail is 67/* to 75/i, and from the anus to 

 the vulva 190/x to 200/*. The vulva is covered by a backward- 

 projecting cuticular flap, which forms the provagina mentioned in 

 descriptions of other members of this genus. There is a knoblike 

 enlargement immediately posterior to the vulva. The vagina is 

 about 475/x long. The eggs in the vagina are 85/x to 90ju. long by 

 30/x to 38.5/ji wide. 



Host. — Mountain sheep {Ovis canadensis). 



Location. — Lungs. 



Locality. — Pikes Peak, Colo. 



Tyj)e specivien.—V.^.'^.M. Helm. Coll. No. 29379. 



This species is named for Dr. George W. Stiles, who collected the 

 material. 



During the early part of 1930, the Bureau of Animal Industry 

 was informed that the deer and elk in the Yellowstone Park, Wyo., 

 were suffering from lungworm disease, and lungworms collected 

 on post-mortem examination by Dr. H. B. Raffensperger, of Miles 

 City, Mont., were forwarded for study. The nematodes collected 

 from the lungs of the elk were identified as Dictyocaulus hadweni, but 

 those from the deer proved to be a new species of Protostrongylus. 



