744 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



Family DYTISCIDvE. 



DytiscidfE sp. 



PI. XXIII, figs. 3, 4. 



The metasternum of a species of Dytiscidae is among the fragments 

 obtained. It is nearly complete, and, of all with which I have been able 

 to compare it, most resembles that of Matns, particularly on account of the 

 depth of the median groove, the form and relative abbreviation of the 

 rounded intercoxal prolongations, and the shape of the coxa?, and it agrees 

 very well in size with our single species, M. licarinatus. As, however, it is 

 not nearly so long in proportion to its breadth as in that species, and nar- 

 rows remarkably from behind forward, it hardly seems possible to refer it 

 to that genus, and I find no other with which I can so well compare it. 

 Instead, also, of being faintly and rather sparsely puuctulate, as in M. 

 bicarinatus, the surface is feebly, longitudinally, and undulately striate, and 

 of a dull piceous color. In the general form of the metasternum it more 

 nearly resembles an Agabus. 



Length of metasternum, 3™™; breadth posteriorly, 5™". 



Family ELATERID^. 



Corymbites (ethiops (Herbst)?. 



PI. XXIII, fig. 2. 



The prothorax of an elaterid of a 2:)iceoi;s color is referred here with 

 some doubt. There are but two or three of our species which have a pro- 

 thorax large enough to compare with it, but the size and general propor- 

 tions, and especially the punctation of the surface, agree perfectly with 

 C. (BtMops. It differs from that, however, in the greater slenderness of the 

 produced posterior outer angles, the sides are more strongly convex on the 

 posterior half, and it is not narrowed to nearly the same extent anteriorly. 

 This last point makes its reference here very doubtful, but until further 

 remains are found it seems be.st to place it here with a mark of doubt. 



Length of prothorax along the median line, 5.35°"°; greatest breadth, 

 5.25"™. 



