324 Dr. T. A. Chapman on the Léfe-History 
sac, pale yellow in colour, with numerous circular markings 
and rounded dots, and is in continual rhythmie movement. 
The tracheal system is very like that of other Coleopterous 
larve ; it is probably the same in the full-grown larva, as the 
positions of the spiracles are the same. From the first to the 
second spiracle the lateral trunk is double; and about its mid- 
dle is a short branch, the abortive second thoracic spiracle: 
the only difference from the Coleopterous type is that there is 
no spiracle in the twelfth segment; but there is a distinct short 
tracheal trunk running towards the skin to represent it. 
Th -grown larva has a very close superficial resem- 
blance to a Crabro or Pemphredon larva. It is 11 millims. in 
length (this is from the fourth to the twelfth segment) ; from 
the jaws to the last segment it is dorsally 21 millims., but 
ventrally 8 millims.; its lateral diameter is 4} millims., its 
antero-posterior 23 millims. It is therefore much flattened ; 
and this flattening is chiefly in front. The head is very small, 
and curved forwards so as to be almost out of sight, the front 
of the head being directed rather towards the body of the in- 
sect than directly downwards. It possesses a pair of triangular 
jaws produced at the apex into an extremely sharp point. 
There is a transverse line beneath these; and there are emi- 
nences, that may be called labrum, maxille, and labium ; but 
I cannot determine the actual mouth-opening or any other 
apparatus, except that a to-and-fro sucking-movement is ob- 
servable among the contents of the head. The second seg- 
ment is rather large, and possesses dorsally a large trefoil boss 
on either side ; it is in the front part of this that the eye-spots are 
visiblewhen they have quitted the larval head. These bosses are 
separated from the head by a narrow smooth surface; a sma 
lateral tubercle intervenes between them and a lateral or ven- 
proper, I think they must be called legs, although they possess 
no corneous plates or claws, and are in fact of the same pel- 
lucid structure as the other tubercles; they appear to assist, 
passively rather than actively, in holding the wasp-grub. The 
ird and fourth segments have each two large dorsal bosses 
or tubercles, with two smaller ones beneath each, and an indi- 
cation of alateral tubercle. The fifth and sixth segments have 
similar but less marked dorsal tubercles. All these segments 
narrowed ventrally. The sixth with the following 
segments form the lossihidinal portion of the body of the 
