40 



characters; in addition, the antennal groove is apparently 

 closed. The new species differs from nudatus as follows: 



Female: The first joint of hind tarsi has three groups of spines 

 on the anterior marg-in. The long- spine on the apex of second 

 joint of hind tarsi extends only to the middle of the last joint. The 

 leng-ths of the hind tarsal joints are in the proportion 22-11-8-5-11. 



Each ventral seg-ment bears two bristles on either side, a large 

 and a small one, the larger one above and behind the smaller. An 

 oblique row of three bristles occurs beneath the pygidium; the 

 upper one is the smallest, the lowest much the largest. Length 

 2 mm. 



Ceratophyllus acutus n. sp. 



Professor Kellogg- has handed to me some specimens 

 collected at Stanford University by a student of his, on 

 the common Spe rmophilus of that region. It is closely 

 related to the other spermophile fleas, coming nearest to 

 idahoensis and arixonensis, from both of which it is well 

 separated by the very different form of male claspers and 

 by numerous minor details. 



Female: Differing from the female of idahoensis as follows: 

 Gena below the eye subacutely pointed posteriorly. Hind margin 

 of antennal groove with several stout hairs below; just back of the 

 margin is a long bristle. The prothorax has a ctenidium of about 

 eighteen stout spines. The raetanotum and first three tergites 

 each have a small stout tooth on either side of hind margin. But 

 two large antepygidial bristles occur on either side. Most of the 

 sternites have single rows of about twelve bristles each; on the 

 seventh sternite there is a second row of small bristles. Beneath 

 the pygidium on either side are three bristles. The eighth segment 

 bears numerous irregularly placed stout bristles. . Style short and 

 thick, somewhat narrowed to the tip where thete is one stout bristle 

 and a smaller one beneath. Hind femora with a longitudinal row 

 of four or five minute bristles on the side. The spines on the under 

 side of fifth tarsal joint stand in uniform rows on either margin. 

 The lengths of the hind tarsal joints are in the proportion 32-19-9- 

 5-13. Length 3 5 mm. 



Male: Hind margin of antennal groove with only two small 

 bristles. Sternites each with a single row of six stout bristles. 

 Lateral portion of ninth tergite with the apical lobe broadly 

 rounded, its margin bearing a few weak hairs and two long bristles 

 over the insertion of the claspers. The upper cla&pers are very 

 long and slender, somewhat enlarged toward the base, the upper 

 two-thirds nearly parallel sided and somewhat curved dorsad. The 

 tips of the claspers are subacutely pointed and the hiud margin 

 bears three or four long hairs. Length 3 mm. 



