160 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



Horn; the latter species is a race of (jigantea., and occurs much 

 farther north in southeiii California." 



Some observers have referred this form also to innocens, which 

 does in some respects resemble it, for instance, in being widest at 

 the posterior fourth of the elytra, the latter having stria' of punctures 

 which are more or less impressed and the intervals more or less 

 convex. Innocens is also more elongate, and the genital characters 

 present a decided subgeneric difi'erence. Compare in Plate rt, figs. 21 

 and 22. 



Eeldt'ioiiships. — InsulaHs is no doubt more closely related to sxh- 

 iiitcDs than to any other species in the United States fauna. It is a 

 true P ramus in genital characters, and not intermediate between 

 Blapt/Us and Eleodes proper as suggested by Linell. 



Geiicr((l ohser rations. — The mentum is variable, and moderate in 

 size. The middle lobe is subtrapezoidal in outline, sides more or" 

 less arcuate with the apex or converging with the apex more or less 

 rounded. 



Prosternum not prominent ventrally. In the insular specimens it 

 is quite evenly, but not strongly rounded, antero-posteriorly between 

 the coxa\ with a small mucro behind; in the peninsular form it is 

 quite horizontal between the coxa^ and terminating behind in a rather 

 strong and subtri angular mucro. Between the coxa^ the surface is 

 more or less strongly punctato-rugose. 



The mesosternum is quite gradually oblique and more or less con- 

 cave. 



The tibial grooves of the femora are usually distinctly evident for 

 the Avhole length of the inferior surface, the floor of each being quite 

 plane and glabrous or more or less punctate; the margins are more or 

 less acute and cariniform. In the peninsular specimens before me the 

 floors are quite glabrous. 



The external borders of the anterioi* tibia> are distinctly carinate, 

 the carina forming the anterior lip of the tarsal groove, which is here 

 clearly indicated and not at all glabrous. 



The middle and posterior tibia' are evidently very faintly or not 

 in the least carinate externally near the base, and the tarsal grooves 

 are indicated in apical three-fourths, margins more or less w^ell in- 

 dicated. The grooves are sculptured like the rest of the tibial surface. 



The protarsi are about of equal stoutness in the sexes. 



Tarsal fornuda : 



Pro. Miso. Mela. Metatibia. 



Male.— 2J 2J 3 5^ 



Female.— 2 2% 3 5i 



o See Proc. California Acad. Sci., 2 ser., IV, Pt. 1, pp. 306 and 349. 



