586 



INSECTA. 



their eggs in or upon tlie bodies of naked caterpillars, or pupae, to which they can obtain easy access. 

 The larT« of the Ichneumons have no feet, and thus resemble those of the following famihes. 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 ; but 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. iiT.—Pinipia manifesiator, depositing its eggs. houey-comb. These cocoous 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 Europaa, 

 describes nearly 1650 species of European Jchneumones 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 be 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 variation 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 Ichneumu- 

 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 prolong-ed 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. 



Stephanas, Jur. (having the thorax very narrow in front, and the antenn* 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 

 ordinary 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 



Pimp/a, 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 gi'ound. [They constitute the subgenus Pezomachiis, Gravenhorst, who has pub- 

 lished a monograph upon them.] 



Others have the ovipositor of the females hidden, or but httle extended beyond the anus. 



0/)/((o«, Fab., has the abdomen sickle-shaped, the antennje filiform or setaceous; the ovipositor is slightly ex- 

 serted. The second cubital cell is very small. Type, Ichneumon lutcus, 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 strobilellae. Fab. 



Banchus, Fab., has similar antenna^, 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 antenns 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.] 



