42 NORTH AMERICAN ANOPLURA 



are triangular in shape with the posterior margin longest and somewhat 

 concave, the posterior angles produced into broad, rounded points. The 

 first bears no hairs, the second, which is the largest, bears a moderately 

 long, stout, blunt hair and a very short one, and the third and fourth 

 each bear two long hairs, in each case that on the dorsal side being the 

 longer. The second segment bears on the ventral side, slightly in from 

 the pleurite, a small chitinized piece, of doubtful homology, but perhaps 

 representing the remnant of the first pleurite. 



On the ventral side of the abdomen all the spines are appreciably 

 shorter and stouter than on the dorsal side, and the number is somewhat 

 smaller. The genital plate is very broad, slightly pointed posteriorly and 

 very convex anteriorly, apparently including a portion of the seventh 

 segment since the row of hairs on this segment extends partly across the 

 genital plate. The gonapods each bear two very short hairs. Behind 

 each gonapod a group of two long stout hairs and two more slender 

 hairs. A short, sharp, stout spine inwardly pointing on the ninth seg- 

 ment. Vulva not fringed. 



Description of the Male. — Length .75 mm., length of head .22 

 mm., length of abdomen .45 mm., width of head .12 mm., width of tho- 

 rax .2 mm., width of abdomen .4 mm. 



In general closely resembling the female except for its slightly 

 smaller size and more pointed abdomen. The number of spines on the 

 abdomen is slightly less than in the female, there being four to six less 

 hairs in each row. 



Basal plate rather short, divided into two slender rods, which are 

 united only at their anterior ends. Parameres shorter than the basal 

 plate, slender, curved inward at the posterior end ; penis very small and 

 inconspicuous. 



Enderleinellus suturalis var. occidentalis n. var. 



Plate II, fig. 3; plate IV, fig. 10; plate V, fig. 17. 



Several males and females from two individuals of Callospermophi- 

 lus chrysodeirus trinitatus (South Yolla Bolly Mt., Tehama county, 

 Calif.). The variety differs from E. suturalis in the conspicuously small- 

 er number of spines on the abdomen and in the shape of the sternal plate. 

 The number of spines on each abdominal segment is from fourteen to 

 eighteen, as compared with eighteen to twenty-four in E. suturalis, and 

 the division into three groups is much more marked. The sternal plate 

 is shorter and more nearly round than in E. suturalis. 



