THE CANADIAN ENTOMOLOGIST 127 



Male. — Length 3.5 mm., elytra not concealing the tip of the 

 abdomen. Otherwise resembling the female. Genitalia very 

 closely resembling the genitalia of Leptiniis testaceus Miill., as 

 figured by Sharp and Muir^. 



Habitat. — From Aplodontia sp. (a genus of rodents peculiar 

 to the Pacific Coast). Fallen Leaf Lake, Plumas Co., Calif., Aug., 

 1917. W. K. Fisher col. 



Types. — Holotype, a female, and allotype, and thirteen para- 

 types, one dissected, mounted on slides and used as the basis of 

 the accompanying figures, deposited in the collection of the De- 

 partment of Entomology of Stanford University. 



Remarks. — ^While this species is obviously very similar to 

 L. validus (Horn) there are certain differences that are apparent 

 upon a comparison with his original description^ and later notes^. 

 L. validus is described and figured as possessing a distinct brush 

 of stiff hairs at the tip of the prosternum, a feature that is not 

 present in the new species, and it is also indicated that the pro- 

 longations of the posterior angles of the mentum are very long 

 and slender, while in my specimens they are short and stout as in 

 Leptinus testaceus Miill. Nor do my specimens possess any trace 

 of the eye spot described by Horn. Certain apparent differences 

 in shape might easily disappear upon a direct comparison of 

 specimens but there is a real difference in size, the new species 

 measuring but 3 mm. in length for the female and 3.5 for the male 

 as compared with 5 mm. for validus. Certainly as far as the 

 literature is concerned there is sufficient ground for recognizing 

 the specimens from Aplodontia as distinct. 



It should be noted that although the prosternum extends 

 back over the anterior coxae it does not actually separate them, 

 and they are in fact fully as contiguous as they are in Leptinus 

 testaceus Miill. 



Mr. Fisher informs me that the specimens were found upon 

 two individuals of the host, and that t hey leave the host, after it 



3. Sharp, D. and Muir, F. Trans. Ent. Soc. London, p. 506; pi. LI, f. 55- 

 5oa. (1912). 



4. Horn, G. H. Trans. Amer. Ent. Soc, 4 : 145-6; figs. (1872). 



o. Horn, G. H. Trans. Amer. Ent. Soc, 10 : 113-4; pi. 5, f. 1-6. (1882). 



