'262 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



denly declivous behind. The femoral teeth are also usually much 

 stouter, longer and more acute, but these last characters are variable 

 and in a large series lose their differential value. 



In the typical race the apical angles of the pronotum are acute, 

 usually prominent anteriorly and dei\tiform. The angles present 

 considerable variation in a large series of specimens, and if the 

 examples be arranged according to the form of the angles, they will 

 be found to pass from that observed in the typical, to small, acute, 

 dentiform and everted in the other extreme of the series. 



These remarks apply also to the femoral teeth; in the extreme 

 forms as opposed to the normal, they become long, slender, and acic- 

 ular, or even shorter and triangular, even obtuse or entirely aborted 

 on the meso- an.d metafemora {forma svhedenfata) , even where there 

 is no change in the l)odily form. 



In the collection of the California Academy of Sciences there is a 

 specimen from Lower California, and referred to luca' by Dr. George 

 Horn, that has only the anterior femora armed and without any evi- 

 dence of the other femoral teeth; this specimen has the facies of 

 arTnata — the elytra being unusually and very gradually attenuated 

 posteriorly, Avithout 'Any signs of the formation of a definite cauda. I 

 believe this specimen to l>e a subedentate aj'/nafa. 



A most interesting series was received from Fresno County, Cali- 

 fornia, by Mr. Fuchs for the California Academy of Sciences. To 

 my mind this series demonstrated the fact that (irinata passes into 

 dentipes by the failure of development in the teeth upon the meso- 

 and metafemora. In the series were specimens Avith the teeth in dif- 

 ferent degrees of atrophy, and some with only the anterior femora 

 armed; in general facies they could not be separated from the un- 

 doubted typical forms hi the same series (see impotens). Many 

 specimens of fully armed armata have the pronotum nearly as 

 strongly sinuate posteriorly as in dentipes. 



General observations. — The mentum is also variable. The middh? 

 lobe may be moderate or smaller in size, subtriangular to trapezoidal, 

 the apex evenly rounded or subtruncate. The surface is coarselv 

 punctate and not noticeably setose, feebly convex centrally and more 

 or less strongly foveate lateralh\ or (pate plane and not foveate. 



The prosternum is strongly sculptured and strongly mucronate, 

 usually horizontally so, and flat between the coxa ; frequently convex 

 between the same and horizontally mucronate, or rarely with a small 

 mucro; sometimes vertically truncate behind, with the angle rectan- 

 gular or strongly mucroid and prominent. 



Mesosternum short, scarcely at all horizontal, nearly entirely and 

 obliquely vertical, more or less strongly concave. 



The abdominal process is subquadrate, a little transverse and just 

 a little wider than the third segment is long. The second segment is 



