108 Psyche [August 



Straits to S. vulgaris and its various subspecies of Europe and Asia, 

 but all have what is apparently the same species of Enderleinellus. 

 The student of these parasites is forced to the conclusion that the 

 problem of their distribution is fundamentally the problem of the 

 genetic relationships of their hosts. 



Enderleinellus suturalis Osborn. 



Many specimens from Callospermophilus chrysodeirus and 

 Citellus heldingi (Yosemite National Park, Calif.) and from skins 

 of Xerospermophilus tereticaudus, (Imperial Co., Calif.), Animo- 

 spermophilus nelsoni (Bakersfield, Calif.), Cynomys leucurua 

 (Routt Co., Calif.), Cynomys gunnisoni (Florissant, Colo.), Citellus 

 mollis (Virginia Valley, Nev.), C. townsendii (Wallula, Wash.), 

 and C. grammurus (Santa Catalina Mts., Ariz.). 



This is a very puzzling species, a slightly different form appearing 

 on each host genus and even on the different host species of the 

 same genus. Some of these forms, such as E. osborni K. & F. ap- 

 pear to be worthy of being distinguished as separate species and 

 perhaps some of the others should be regarded as varietal ly dis- 

 tinct. The form occurring upon Callospermophilus has been given 

 the varietal name of occidentalis and this name may be retained for 

 the present, although it is no more worthy of being so distinguished 

 than are some of the others. 



The host of the type of the species is Citellus franklini (Ames, 

 Iowa) . 



Enderleinellus uncinatus sp. nov. 



From Glaucomys sabrinus lascivus (Yosemite National Park, 

 Calif.). 



This is probably the smallest known species of Anoplura and it 

 is unique in other respects as well. In fact it is of such peculiar 

 character that it might well be regarded as the type of a new genus. 

 However, its affinities are clearly with Enderleinellus and in the 

 present state of our knowledge of the Anoplura it is well to move 

 slowly in the matter of multiplying genera, hence it seems best to 

 regard this as an aberrant Enderleinellus. 



Its affinities with Enderleinellus are shown in the character 

 of the legs, the anterior and middle pairs being small and the pos- 

 terior pair large and stout. The undivided abdominal tergites 



