384 Mr. R. C. L. Perkins on 
this spur. The common insect called by Saunders Solenius 
vagus appears to be congeneric with Xestocrabo, Ashm., but 
Ashmead’s restriction of Solenius, if correct, excludes any 
British species from the latter, the American Solenius being 
very different in structure. I do not think that the genus 
Stenocrabro, Ash., is valid. It would probably contain our 
Crossocerus varius, ete., but it was based only on male 
characters. The American hymenopterist also largely 
employed sculpture in his generic divisions, and, I think, 
went too far in this respect, though not without some fair 
reason, when one examines the North American species of 
Crabronidae, where, as elsewhere, a similar style of sculpture 
runs through whole series of species. According to the 
same author the genus Coelocrabro, Thoms., is a synonym 
of Blepharipus, Lep., Morawitz having subdivided the latter 
previously. Our British species that stood under Blephari- 
pus (Coelocrabro) are a very heterogeneous assemblage and 
are sure to be further ce eee while one of them, 
B. podagricus, cannot possibly be considered as congeneric 
with the others. Crabro vagabundus, Panz., also appears to 
me to have very distinct generic characters. I have not 
been able to critically examine specimens of B. styrius, and 
it is possibly misplaced in my table and not really closely 
alhed to B. capitosus. Two species (C. elongatulus and 
wesmaelv) are a discordant element in the genus Crossocerus. 
The minute tubercles at the sides of the mesosternum 
in the small species of the Thyreopinae require careful 
examination, because the margin of the coxal cavities 
behind these is sometimes a little prominent, and might 
be mistaken for these tubercles. The latter are always 
placed well in front of the coxal cavities, at the point 
where the mesosternum slopes down to the latter, and in 
fact are the homologues of the carinae of the Crabroninae. 
I have referred to these structures indifferently as being 
‘spinose ” or “ tuberculate,” as the tubercles are often 
pointed. Owing to the interference of the dense clothing, 
it needs a little practice before it becomes easy to see the 
important structures of the clypeus, and to do so is greatly 
facilitated by opening the mandibles. The mandibular 
structure is so important and interesting in the Crabronidae, 
that these organs should always be spread open in some 
individuals of a species, and since only a few species are 
so small as 5 or 6 mm., and many are large insects, it 
requires very little skill or trouble to do this, when the 
