1917] New Species of Mallophaga 169 



near the junction of the head and prothorax, and a long hair just mediad 

 of these. Antennae joints of nearly equal thickness, but with the third 

 nearly equal in length to the other two. 



Thorax about two and one-third times as wide as long. Prothorax 

 rather lenticular in outline, with the median portion of the hind margin 

 decidedly convex. A weak spine on each side at the outer ends of the 

 anterior margin, and a stronger hair on each lateral margin just over the 

 conspicuous, protruding spiracles, and a long hair on each side near 

 the hind margin midway between the median line and the lateral border. 

 Metathorax w^th rather abruptly converging sides, the conspicuously 

 concave posterior margin fonning nearly right angles with the lateral 

 borders. A very short spine at each anterior lateral angle, three long 

 hairs arising behind these so that bases form curves bending backward 

 and inward from the spines at the angles. About eight hairs arise 

 along the median part of the concave margin. , Legs conventional. 



Abdomen widely oval in outline, broadest on the second and third 

 segments. First segment with a series of eight or nine hairs at the 

 anterior margin medially, and with four or five spines along the lateral 

 margin. Segments one to six, inclusive, with a stiff hair near each 

 posterior lateral angle, and segments one to seven, inclusive, each with a 

 transverse series of from sixteen to twenty four dorsal spines. Segments 

 two to seven, inclusive, with a rather distinct spiracle on each lateral 

 margin. Terminal segment rather deeply emarginate medially, with 

 a central cluster of four dorsal spines, a transverse series of four weak 

 spines, and a longer spine at the middle of each lateral border. 



Trichodectes thomomyus n. sp. 



Two females and one male (Bishopp No. 2604) from 

 Thomomys sp., Jefferson, Colo., May 7, 1912, C. Birdseye, coll., 

 and one immature specimen (Bishopp No. 2606) from the same 

 host and locality. May 12, 1912. 



This species is most nearly allied with T. geomydis Osb., from 

 which it is easily distinguished by the absence of a process on 

 the second joint of the female antenna which are inserted 

 before the middle of head; the straight, truncate hind margin of 

 head; and by the shape of the metathorax. 



Description of Female. — Total length, 1.111 mm.; length of head, 

 .314 mm.; length of prothorax, .0837 mm.; length of metathorax, 

 .0418 mm.; length of abdomen, .68 mm.; width of head across temples, 

 .398 mm. ; width of prothorax, .298 mm. ; width of metathorax, .387 mm. ; 

 width of abdomen, .586 mm. 



Head nearly a third again as wide as long, with a distinct, some- 

 what V-shaped median emargination, produced into stout, trabecula- 

 hke processes just before each antenna. Antennal sinuses only fairly 

 deep, but of considerable longitudinal span. Ocular projections lacking. 

 Temple margins at first are nearly parallel , but at their midpoints bend 

 abruptly inward and meet the occipital margin at an obtuse angle. 



