PHILIP P. CALVERT 347 



The occiput of the male has shallower dorsal pits and no supero-postorior 

 tubercles, and the rear of his head is not differentiated into pit and ridge 

 behind each eye. 



Epigomphus subsimilis (PI. XIII, figs. 1 to 3, 5 to 7.) 



Of the seven females of this species none show any scars on 

 the eyes or in the region of the ocelU comparal)le to those ob- 

 served and described for E. verticicornis and other species, al- 

 though two of these females yielded eggs from which larvae 

 subsequently hatched, so that these two females must have 

 paired. On the rear of the head, laterad to the level of each 

 lateral end of the occiput (and consequently laterad to the level 

 of the meso-dorsal margin of each compound eye) is a moderately 

 deep pit (fig. 7, p); in each of these is one or two impressions 

 which are probably cicatrices. Laterad to each pit is the in- 

 ferior end of a pronounced vertical ridge (r, same figure), the end 

 of which appears as a tubercle in a dorsal view of the head (fig. 

 5, r). Laterad this ridge is sharply delimited by a subvertical 

 groove (g). A comparison of the male abdominal appendages 

 and the female head makes it likely that when pairing the mesal 

 apical angle of his superior appendage, with its ventral subacute 

 process (fig. 2, //) is received into the pit {p) and that the lateral 

 apical angle ig') of the same enters the groove, g, perhaps near 

 or at its superior end. The position assumed by his inferior 

 appendage is much more conjectural, but a reasonable hypoth- 

 esis would be that the two apices thereof {prs') are lodged in her 

 parocular grooves (prs) between the lateral ocelli and the mesal 

 margins of the eyes. 



There are no such pronounced tubercles posterior to and dis- 

 tinct from the elevations on which the lateral ocelli lie as in E. 

 verticicornis. The slope cephalad from the occiput to these ocelli 

 is gradual, whereas in verticicornis the posterior wall of each post- 

 ocellar tubercle rises almost vertically, thus furnishing a firm 

 support against which the distal margin of the male's inferior 

 appendage may be braced when pairing. Here no such possi- 

 bility apparently exists. 



On the dorsal surface of her occiput are two pits (fig. 5, dof) 

 near the two lateral ends thereof; their appearance suggests 

 that of the similarly situated depressions in some females of 



TRANS. AM. ENT. SOC, XLVI. 



