DESCRIPTIONS AND DETEP MI NATIONS OF SPECIES 23 



of the type usual in the genus, except that the projection on the anterior 

 margin of the tibiae of the third pair is extremely small. 



Abdomen elongated oval. First segment with one sclerite bearing 

 two widely separated pairs of slender hairs, each sclerite of the third 

 segment with seven hairs of the same type. Fourth to seventh segments 

 each with three sclerites and ten to fourteen small, awl-shaped spines. 

 Eighth segment with one sclerite and six spines. Ninth segment with 

 two very small hairs. 



Pleurites of the first segment small and tooth-like, those of the sec- 

 ond segment with a short knife-like process at the ventral posterior angle, 

 and a short tooth at the dorsal posterior angle, and two hairs on the pos- 

 terior margin. Pleurites of the third to sixth segments with a slender, 

 rather long tooth at each posterior angle, and two hairs on the posterior 

 margin. Pleurites of the seventh and eighth segments small, not toothed 

 and with two long hairs. 



On the ventral side the first segment apparently lacking, the second 

 with one row of six small spines. Third to seventh segments with three 

 sclerites each, all except the first sclerite of the third segment bearing 

 six to eight awl-shaped spines. The first sclerite of the third segment 

 bears eight spines, of which the median pair are very small, and the re- 

 mainder large and conspicuous, the outer spine on each side being bent 

 inward. 



Genital plate bluntly pointed posteriorly, with four small hairs near 

 the tip. Gonapods with two small hairs and one large hair. Caudad of 

 each gonapod a group of three or four stout hairs, a stout spine and sev- 

 eral small hairs at the posterior angles of the ninth segment. 



LINOGNATHOIDES Cummings. 

 Linognuthoides Cummings, Bui. Ent. Res., vol. 5, pt. 2, pp. 159-160, (1914). 



Resembling Polyplax except for the absence of definite, well chitin- 

 ized tergal and sternal plates. Antennae of the male without a preaxial 

 process on the third segment. 



This genus is very close to Polyplax, yet it seems to form a well 

 differentiated group. It was but recently established by Cummings for a 

 single species, L. spermophili, taken from a species of Spermophilus and 

 also from a Murid in i\sia. In the paper in which the genus is defined 

 Cummings suggests that an American species, Polyplax (?) montanus 

 (Osborn) should be referred to this genus, and this surmise we find to 

 be correct. In addition to this species, we are recording two new species, 

 one from a Murid and one from a Geomyid. 



