270 BULLETIN 6.3, UNITED STATES NATIONAL MUSEUM. 



The series at hand does not support Doctor Horn's statement in 

 regard to the form of the prothorax in the two sexes. A male from 

 Santa Margarita Ishmd has the base of the prothorax notably wider 

 than the apex and tlie sides do not converge at base ; a series of six 

 females from Lower California (mainland) have the prothorax snb- 

 quadrate, base slightly wider than the apex, and the sides converge. 



The series is not large enough to decide this question; evidently 

 the prothorax is variable; it is to be noted that the specimens are 

 from two separate and distinct regions. The male is often more 

 robust than the female. 



In several males before me the femora are very stout, compressed, 

 and quite broad ; the femoral teeth are stout and subequilaterally 

 triangular. 



The elytral stria? may be quite strongly impressed at times, with 

 the intervals feebly or moderately convex. 



This species is probably a southwestern modification of arriiata. 

 Forms occur in Arizona which can not be separated from this species. 



A specimen collected at Palm Springs, California, and recently re- 

 ceived for identification, has the integuments more opaque, form 

 more robust and oblong, elytra with the sides feebly arcuate and more 

 rapidly narrowing in ai)ical fourth; elytral punctures fine and equal 

 in both series; antenna; slender and elongate, the femora compara- 

 tively slender and the anterior femoral teeth small. 



Two specimens under examination have the general form of mUi- 

 tarh^ although more elongate; the anterior femora are alone armed, 

 the middle and posterior being edentate. One of these specimens was 

 collected at San Quentin, Lower California (collection California 

 Academy of Sciences), and referred to luccv by Doctor Horn. I do 

 not believe that it should be referred to that species, for the facies is 

 not that of laca', and I have found that the prothorax may vary suffi- 

 ciently in almost any species to simulate that of another. T have 

 demonstrated to my own mind that armata may become subedentate 

 by loss of the teeth of the middle and posterior femora, and thus pass 

 into dentipes: furthermore, I see no reason why miVfarix and femo- 

 rata should not vary in a similar way. 



In both specimens the epipleura? at the elytral apices are dilated a 

 little more than usual for species of the present section, but I consider 

 this character more of a fortuitous exaggeration. of the indifferent 

 stage of the caudal development, or jiossibly it is atavistic reversion. 

 The relationship of this interesting form can not be determined until 

 better collecting has been done on the peninsula. T therefore for the 

 present define this form as follows: 



Forma subedentata. — Form as in militarise with the anterior femora 

 alone armed. 



