HYMENOPTERA. —— ICHNEUMONIDE. 141 
My figure 76. 1. will show the mode in which the abdomen of those 
species with short ovipositors is bent beneath the body, in the act of 
oviposition. This figure represents an Ichneumon (sp. ?) depositing 
its egg in the body of a young Syrphus larva, which is engaged in 
sucking an Aphis.* In those species which have a long ovipositor, 
it is ordinarily porrected in a straight line during rest ; but in those 
with a short ovipositor, it is generally carried in a more or less 
oblique direction, pointing upwards; but when the insect is dis- 
turbed, or in the act of oviposition, it is disengaged from the sheaths, 
and is directed upwards and downwards (Gravenhorst doubts its 
lateral motion) at every angle from the line of the body. 
The species are of small, or but moderate size; their colours are 
generally black, varied with red, yellow, or white; and the antennz 
are often marked with a broad annulus of pale colour. 
The name of Ichneumon has been given to these insects (which 
are parasitic upon other insects), from the similarity of their habits to 
that which has been fabulously attributed to the quadruped of that 
name, namely, that of depositing its progeny in the body of the 
crocodile, the entrails of which are by degrees devoured by the para- 
site. Other old authors have named these insects Musce tripiles, from 
the sete of which the ovipositor is composed ; whilst others called 
them Musce vibrantes, from the constant vibration of their antenne, 
whereby they are enabled in some manner to acquire a knowledge of 
* May 29. 1830, I observed a Pimpla with the ovipositor about as long as the 
body in the act of oviposition ina dry paling, which had been much perforated, and out 
of which I had just dug a black Pemphredon. The part in which the ovipositor 
was introduced appeared to be quite solid. (Réaumur represents his specimens 
as inserting their ovipositors in a circular patch of dried clay, used to stop up the 
entrance to the nest of the intended victim.) There are several very minute blackish 
spots, as they seemed to be, close to the place where the ovipositor was inserted, 
and which were probably other places of insertion of the ovipositor. When first 
observed, the insect had introduced about half the terebra into the post, the part 
remaining uninserted being at a right angle with the body, the sheaths being 
curved, their tips being brought to the place of insertion, thus evidently strengthen- 
ing the terebra in its operations ; the abdomen was at this time alternately turned 
from left to right, and vice versa, whereby a brad-awl kind of motion was given to 
the terebra, enabling it to penetrate the wood toa greater depth. It then alter- 
nately partially withdrew, and replunged the terebra into the hole thus made, as 
though in the act of passing an egg or eggs, standing all this while on the tips of 
the tarsi. On cutting, however, into the post, I was not able to discover any 
lignivorous larva, finding only a channel of fine white pulverised wood, which had 
been made by a previous occupier of the tube. 
