XXVI. PEMPIIREDON. 195 
this genus as it stands in Latreille, especially as he has 
more recently done so in Gorytes and Crabro upon much 
less justifiable considerations, which may be seen in the 
observations I have made under those genera. In follow- 
ing out the alary system, which I consider the chief and 
best mode whereby the fossorial Hymenoptera may be 
naturally subdivided, I have been obliged to re-establish 
Jurine’s genus Cemonus, which St. Fargeau and V.d. Lin- 
den had suppressed, as also to form two new ones; thus 
the insects which in Latreille, St. Fargeau, and V. d. Linden 
constitute the sections and subsections of one genus, I con- 
sider as forming five, viz. Diodontus, Passalecus, Pem- 
phredon, Ceratophorus, and Cemonus ; and my views ap- 
pear to be confirmed by each genus containing species 
which agree precisely in habit, with the exception of the 
P. morio of V. d. Linden, which stands solitary, but differs 
so considerably from the typical Pemphredon, that V. d. 
Linden must have separated it, at least from its contiguity 
to the P. lugubris, could he have examined it. The different 
form of its second submarginal cell, the shape of its head, 
the bidentate mandibles in the ¢, tubercle of the face, 
Jarge labrum, short petiole of the abdomen, all combine 
to produce a very different habit, which agrees better with 
the genus Diodontus, from which however it sufficiently 
differs, especially in the entire labrum and distinctly pe- 
tiolated abdomen ; in the tubercle of the face it resembles 
Passalecus, m1 which however it is acute and not emar- 
ginate, and in the sculpture of the metathorax a Cemonus. 
Had I been acquainted with the insect before my table 
was printed, I should certainly have treated it as a genus, 
and which I now propose by the name of Ceratophorus, 
xépas, a horn, ¢opos, bearing, from the tubercle of its face. 
02 
