586 
INSECTA. 
their eggs in or upon the bodies of naked caterpillars, or pupae, to which they can obtain easy access. 
The larvae of the Ichneumons have no feet, and thus resemble those of the following families. Those 
which reside, like intestinal Worms, inside 
the bodies of other insects, sometimes in so- 
ciety, devour only the fatty parts of the body, 
being the portions not absolutely necessary 
for existence ; hut when ready to assume the 
pupa state they pierce through the outer 
skin, or else they kill their victim and un- 
dergo their own changes in its body. The 
majority spin a silken cocoon, in which the 
pupa is inclosed. These cocoons are some- 
times united in a mass, sometimes naked, and 
sometimes enveloped in a common cottony 
mass, often seen attached to the stems of 
plants. Their union and arrangement forms 
a mass sometimes resembling a piece of 
Fig^. iiz.—Pimpia manifestator, depositing its eggs. houey-comb. These cocoons are sometimes 
of a uniform whitish colour, and sometimes banded ; some cocoons are suspended to the leaves of trees 
by a long thin thread. 
This family is extremely numerous in species. [Gravenhorst, in his Ichneumonologia Europtea, 
describes nearly 1650 species of European Ichneumones genuini ; and Stephens and others have added 
greatly to their number. The Ichneumones adsciti are probably as numerous ; so that, supposing the 
number of species in the world to he double that of those found only in Europe, we shall have more 
than 6,000 Ichneumonidae ; a number which, although very extraordinary, is probably far below the | 
actual amount.] 
The vai-iation in the number of joints in the palpi may serve as the basis for the principal divisions in the 
family. [This character has been proved by Haliday and Nees von Esenbeck to be inapplicable to the Ichneumo- 
nides adsciti.'] 
The first comprises those species which have the maxillary palpi 5-jointed, and the labial 4-jointed ; the second 
cubital cell is very minute, and nearly circular, or wanting. 
A first subdivision is formed with the species which have the head not prolonged into a beak ; the labrum not 
deeply notched ; the maxillary palpi very long, and the ovipositor not covered at the base by a large vomeri- 
form plate. 
Some of these have the ovipositor exserted. 
Stephanus, Jur. (having the thorax very narrow in front, and the antennae attached to the posterior and superior 
part of the metathorax, as in the Evaniae, — exotic insects), and 
Xorides, Latr. (having the metathorax convex and armed at the apex, so that the abdomen is attached in the 
oi’dinary manner with a distinct peduncle), differ from the others by having the head nearly globular, the mandibles 
terminated in an entire point or slightly emarginate. The second cubital cell is often obsolete. 
The others have the head transverse, and the mandibles distinctly bifid at the tip. Some, as 
Pimpla, Fab., have the abdomen cylindrical and very shortly peduncled. [Numerous British species.] Type, 
Ichneumon persuasorius, Linn. Another species (P. ovivora, Bull. Ferussac), destroys the eggs of Spiders. 
Cryptus, Fab., has the abdomen nearly oval, with a long curved peduncle. Some of the species are apterous, 
whence, as well as from the form of the thorax divided into two nodes, they should constitute a distinct subgenus. 
They are always found on the ground. [They constitute the subgenus Pezomachus, Gravenhorst, who has pub- 
lished a monograph upon them.] 
Others have the ovipositor of the females hidden, or but little extended beyond the anus. 
Ophion, Fab., has the abdomen sickle-shaped, the antennae filiform or setaceous ; the ovipositor is slightly ex- 
serted. The second cubital cell is very small. Type, Ichneumon luteus, Linn., [a common British species], the 
female of which deposits her eggs on the body of the larva of the Bombyx vinula, fixing them by means of a long 
peduncle. The larva of O. moderator, Fab., destroys that of another Ichneumon, Pimpla strobilellce. Fab. 
Banchus, Fab., has similar antennae, but the abdomen is gradually narrowed to the tip. [B. pictus, Fab., a com- 
mon British species.] 
Hellwigia, Gravenh., have the appearance of the preceding, but the antennae are clavate. [A continental 
species.] 
Joppa, Fab., differs from the following in having the antennae dilated in the middle, and pointed at the tip. 
[Exotic species.] 
