THE ICHNEUMONS. 



contents of its body. In. some cases the Ichneumon larva makes its way within the body of its host, 

 and becomes an internal parasite ; in others it remains permanently on the outside, its hinder extremity 

 beino- always enclosed between the valves of the egg-shell, and then, its body being very translucent, 

 the transfer of the substance of the host to the parasite may be observed going on very actively. 



In the genus Evania and its allies we find a very curious arrangement. The abdomen, instead 

 of springing from the back of the thorax immediately above the hinder coxae, is lifted up, so that its 

 thin petiole is attached just beneath the back of the metanotum. In Evania the abdomen is so 

 small as to appear only like an appendage to the thorax ; hence the best-known species has been 

 named E. appendigaster. It is a small black insect found in the South of Europe and in all tropical 

 countries. It is parasitic upon Cockroaches. An allied British genus (Fcenus) has a very long, 

 slender abdomen, and the prothorax produced into a thin neck. Fcenus jaculator is a not uncommon 

 species found haunting the burrows of Crabronidae, upon which it is probably parasitic. The 

 American genus Pelecinus, which has been placed 

 with these forms, although its abdomen is attached 

 in the ordinary position, is remarkable for the very 

 disproportionate length and slendemess of the 

 abdomen in the females. P. polycerator, which 

 inhabits both North and South America, attains a 

 length of two inches, five-sixths of which consist 

 of abdomen. 



In the group of typical Ichneumonidae, we have 

 already referred to the genera Ophion and Paniscus, 

 and their peculiar habits in the larva state. Many 

 species of these, and allied genera, in which the 

 abdomen is compressed, and the ovipositor short, 

 are to be met with in Britain. In the genus 

 Ichneumon proper, and many others allied to it, 

 the ovipositor is also short, but the abdomen is 

 either depressed or convex above. Cry plus has a 

 nearly ovate abdomen and a projecting ovipositor ; 

 whilst in Pimpla and a number of other allied 

 genera we find a long ovipositor for attacking 

 concealed larvae. A species of Pimpla (P. manifes- 



tator) is figured on p. 1. It is a handsome black insect with red legs. The body measures thirteen 

 lines, and the ovipositor seventeen lines in length, so that the whole insect is two inches and a half 

 long. Many exotic species are larger, and have still longer ovipositors. In these insects the sheaths 

 of the ovipositor serve as guides for the instrument itself when penetrating into hard bodies. 



A large group, chiefly consisting of small species, is that of the Braconides, which differ from 

 the typical Ichneumons in having the first submarginal cell more or less separated from the discoidal 

 cell, and only one recurrent nervure, instead of two. Some of them have the ovipositor projecting ; 

 in others it is concealed. The abdomen is generally more or less ovate. The typical genus Bracon 

 includes an immense number of species, and these are among the largest of the group. One of the 

 best-known species is the little Microyaster c/lomeratus, which is parasitic upon the caterpillars of 

 the common White Butterflies. The larvae burst forth from the body of the caterpillar when it is 

 ready to change, and form round its empty skin a little heap of yellowish cocoons. Aphidius and 

 some nearly allied genera include minute species which are parasitic upon Aphides. 



FAMILY PROCTOTRTJPID^E. 



A vast multitude of small parasites form this family, distinguished from the preceding by the 

 structure of the fore wings, which have a distinct stigma on the anterior margin, but no complete 

 cells, the veins being generally reduced to a few hardly perceptible longitudinal ones. In a great many 

 species the wings are altogether wanting. The antennae vary in structure, being either straight or 

 bent, and they usually consist of fourteen or fifteen joints, but sometimes only of eight. The eyes 



TANISCUS VIRGATUS (A), WITH YOUXG (B) AND OLD (c) 

 LARVJE. , EGG-SHELL. 



