©: FEF) 
the cubital cells are named in the order of their appearance, 
counting from the stigma; 10. 11. 12. are the discoidal 
cells ; 13 and 14. the apical cells, which are frequently con- 
fluent together as well as with the third discoidal. 
The conspectus at the end of this introduction gives a 
tabular view of the neuration of the wings; but I may be 
allowed to remark here upon the singularity of one genus 
only (Cemonus*) receiving both the recurrent nervures in the 
first sub-marginal cell, and that but two insects (Stigmus 
and Celio) have but one recurrent nervure. Only those just 
mentioned and those which have but one sub-marginal cell, 
viz. Oxybelus, Crabro, and Trypoxylon, receive the recurrent 
nervure in the first sub-marginal cell. Three sub-marginal 
cells seem to be the most prevalent number. I am acquainted 
with but one sexual disparity in the nervures of the wings, 
which is the open marginal cell in the females of Tiphia, 
it being closed in the males. The size of the wing is not 
always in direct connection with the power of flight, but 
all these insects are rapid fliers, and most active during the 
greatest heat of the day. In one genus (Pompilus) how- 
ever the wings do not seem always used for flight, for it 
* I know only in this instance, in Mellinus and in the exotic genus Lorrheum, 
Leach (type, Chlorion compressum, Fab.), that where more than one sub-marginal 
cell is present, the second does not receive a recurrent nervure. In Lorrheum 
and Mellinus it is the more remarkable, as it neglects the second to be received 
by the third; but the former insect is extraordinary in other respects,—it is the 
only fossorial insect whose tarsi have foot cushions, and the two projecting spines 
at the apex of its metathorax are singular appendages. The foot cushions would 
indicate a more fully developed power of walking against gravity, and, conse- 
quently, refer to some extraordinary peculiarity in itseconomy. The approximate 
group, the Vespadz, have it also. Is it like them social in its habits? I apply 
Leach’s MS. name to this genus instead of Jurine’s Ampulex; for, notwith- 
standing what the latter says, there is a great difference in the neuration of the 
wings if his figure and the C. compressum be closely compared together. British 
Entomologists must pardon me this exotic morsel. 
