132 Mr. J. O. Westwood’s Memoirs 
ovipositor of Pimpla, (a genus of Ichneumonide, in which it is very 
long, exserted, and slender,) ‘‘ How the egg is propelled, so as to 
pass in safety from the oviduct a/ong this extended and very slen- 
der instrument to the grub for which it is destined, has not been 
certainly ascertained ; but from an observation of Reaumur’s, it 
should seem that it is aided in its passage by some fluid ejected at 
the same time with it, or is so lubricated as to slide easily with- 
out being displaced.” * From these remarks, however, we might 
almost infer that it was supposed that the egg passed along the 
exterior surface of the terebra, but since in the Tenthredinide the 
eggs are conducted between the saws, I think there can be no doubt 
but that they are placed in such a similar situation in the abdomen 
of the female Ichneumons, &c. that they must pass within and be- 
tween those organs which are analogous to the sheaths and saws 
of the Tenthredinide, and which have here become tubiform, and 
which, there is little doubt, have also the power of being opened 
and expanded on the under surface. 
I do not intend to enter into a detail of the structure of the sting 
and ovipositor of the aculeate tribes, but shall only observe, that 
Latreille expressly says that the eggs do not pass through the 
former ;} and that Messrs. Kirby and Spence describe the ovipo- 
sitor as ‘‘ the instrument of oviposition, being in some genera used 
as a weapon of defence, when it is called the aculeus ;” { and also 
they remark, that the stings of some Hymenoptera are analogous 
to the ovipositors of the majority of that order.§ The manner in 
which the aculeate tribes deposit their eggs is, I believe, as yet, 
also unrecorded. || The plates, however, of Swammerdam may be 
consulted upon this subject by the student with great advantage, 
although this author was under the necessity of leaving the manner 
in which the eggs are excluded in doubt. (See his p. 205.) 
I consider it therefore sufficiently proved that X:phydria belongs 
* Introd. vol.iv. p. 211. ‘ Le tube ovipare de cette espéce ( Pimpla atrata, F., 
the largest Ichn., six inches long), est envelloppé d’une gaine élastique, dont les 
parois cédent lorsque l’animal veut atteindre la chrysalide enfoncée dans quelque 
fente ou ouverture d’un arbre.” Bull. Sc. Nat. Jan. 1828, p. 163, (Notes sur les 
Ichneumons en général, by Dalman, from the Swedish Trans. for 1825.) 
+ Gen. Crust. vol. iv. p. 51. 
¢ Introd. vol. iii. p. 390. 
§ Ibid. vol. iii. p. 717. 
|| It may be worth noticing, that in a female of some Bombus which I took in 
copula, the sting was entirely protruded out of the abdomen. 
g As however the structure of the sting is perfectly similar to that of the ovi- 
positor of the Ichnewmons, and as the egg in the latter passes down the ovipositor 
(see Lewis’s papers in Mag. Nat. Hist,), it is agreeable to analogy that the eggs 
of the Aculeata pass down the sling. 
