142 CRABRONID2. 
ovate spot on each side, the fifth sometimes entire, and the sixth 
always so. 
4 ¢ in most Cabinets. 
+4+ It will be necessary for me to state my reasons for 
considering this a new species, although exceedingly like 
two that have been described, viz. [1] the C. fossorius, 
Linn., which is that of all subsequent authors, excepting 
Van der Linden, who, although he cites their synonymes, 
describes a different insect, ([2] which St. Fargeau considers 
as his Cr. chrysostomus,) and St. Fargeau, who has carried 
it into his genus Solenius, but under the same specific 
name. ‘That it cannot be the first is proved by its having 
a golden pubescence on the clypeus ;* nor can it be Van 
der Linden’s Cr. fossorius, which, according to St. Far- 
geau, is his own Cr. chrysostomus ; and the position of the 
stemmata in mine must prevent its being considered as 
this, for Van der Linden does not notice their curve, which 
* The male is in its antenne either a Crabro or Ceratocolus of the second 
subdivision of the first division of St. Fargeau. Why I am uncertain is, be- 
cause in his genus Crabro the stemmata are in a triangle, and the males have 
several of the basal joints of the clavolet emarginate, and thirteen joints to the 
organ ; and in Ceratocolus the stemmata are placed in a curve; and in the 
division I refer to, the antenne of the ¢ have twelve joints, with some of the 
basal ones emarginate. If therefore he overlooked one of the joints, it would 
strictly enter into that subdivision of his Ceratocolus: if he saw the thirteen 
joints, and overlooked the position of the stemmata, it would be a Crabro: but 
if he saw the situation of the stemmata, as well as the thirteen joints of the an- 
tenn, it would have required the establishment of a distinct genus; whereas 
the female is a true Solenius. I have entered into this critical explanation to 
show an additional reason for my not adopting his genera, and which I shall 
further vindicate in several other species. The essential character of a genus 
should be perfectly exclusive and negative for those without it, but positive for 
those within it; nor should the sexes admit of separation; and such a cha- 
racter in this variable genus can be derived only from the neuration of the 
wing, which I also reiterate for the whole of the Fossorial Hymenoptera. 
