XXI. CRABRO. 4g 33) iene 
certainly the most eccentric genus amongst the fossorial 
Hymenoptera ; it varies in habit so very much from the type 
that, exclusive of the generic character of the wings, there 
is nothing to hold it together ; but this is amply sufficient. 
British Cabinets had separated my section B. of the 
synopsis of the species from the rest, by the name of Rho- 
palum; but as it differs in nothing but the subpyriform 
petiole of the abdomen, and to which we have a connect- 
ing link in the C. dimidiatus, I reject it. The arrangement 
by colour is preserved only on account of its bringing the 
larger species together, but it certainly is not that of their 
affinities ; nor even will my synopsis of the species reduce 
them to this order, as it is wholly artificial and constructed 
solely for the purpose of arriving readily at their descrip- 
tions: but they are so exceedingly anomalous that they 
will not at all arrange in a consecutive series. St. Fargeau 
has divided the species with which he was acquainted into 
eleven genera, nine of which we possess ; but as I do not 
consider the characters he has selected to establish them of 
generic value, I have reduced them to synonyms, but 
which will show where they can be applied. His generic 
divisions do not always correspond with their characters, 
and these errors I have pointed out wherever they occur in 
British species. But it will perhaps be expected that I 
should show better reasons for wholly rejecting all the 
genera he has introduced. The most pertinent is to be 
found in my admitting merely the neuration of the wings 
as a generic character. Yet of those derived from the errors 
of his system I will cite a few in justification, and refer for 
the rest to the synonyms and observations under each 
species—thus, the sexes of my C. Lindenius would be 
separated and placed under his Ceratocolus and Solenius. 
The only tangible characters whereby he separates his genera 
