ICHNEUMONID^E. 821 



the tip ; in the former case the abdomen is thickened ( mould or mildew, which, on minute examination, was 



at the extremity, and obliquely truncated. The cen- 

 tral piece of the ovipositor is the only part which is 

 employed in introducing the eggs of the insect into 

 the bodies of those insects which are selected by the 

 females for their reception ; it is more horny than the 

 external sheaths, and of a brighter colour. Although 

 this instrument is very analogous in its construction 

 to the sling of the bee, it cannot in strictness be re- 

 garded as such an organ, although the ichneumon, 

 when held in the fingers, endeavours to employ it in 

 a similar manner by attempting to prick the hand ; no 



effect, however, is to be apprehended from the 



ill 



workings of the instrument : in those species, how- 

 ever, which have the ovipositor short, the organ is 

 certainly capable of piercing the skin in tender parts, 



found to be fine white sand, delicately closing up a 

 hole made by the wild bee, Chelostoma maxillosa, for 

 the reception of her cells, and which, no doubt, con- 

 tained the larva of that insect. The writer hereof 

 has, however, often watched these and other species 

 of the family boring into palings, without being able 

 to perceive the slightest trace of any operations per- 

 formed by other insects, although it is not to be ques- 

 tioned that the larvae of some insect or other were 

 ascertained by the Ichneumons to be in such spots, at 

 a depth in the solid wood. In deep holes which 

 were not closed, the Pimpla not only thrust in the 

 entire ovipositor, but in some cases the whole of the 

 abdomen and posterior legs, leaving out only the two 

 fore legs and the wings, which it spread out in oppo- 



and of causing a slight pain, arising, probably, rather [ site directions, like arms. At such times the external 



from the wound than from any deleterious fluid intro- 

 duced at the time. These insects were comprised 

 with some other parasitic groups, as the Chaladidte 

 and ProctotrupidcE, in the Linnaean genus Ichneumon, 

 a name given to these insects by the ancients, from 

 the services which they performed to agriculturists 

 by the destruction of vast numbers of caterpillars, 

 in the same manner as the quadruped named Ichneu- 

 mon was supposed to destroy the posterity of the 

 crocodile by the Egyptians, who considered that the 

 former animal not only demolished the eggs of the 

 latter, but even killed the crocodile by introducing 

 itself into its body, and devouring its entrails : the 

 antilogy does not, however, entirely hold good, since 

 the Ichneumon fly merely deposits her eggs within 

 the body of the caterpillar, the grubs hatched from 

 which devour its entrails by degrees. 



We are indebted to Mr. Marsham for an account 

 of the proceedings of one of the largest British spe- 

 cies, Pimpla manifestator, which is provided with a 

 very long ovipositor, published in the third volume of 

 the Linnsan Transactions, and which it may be ser- 

 viceable to detail as giving a general notion of the 

 habits of the family. This species was observed by 

 him on t4ie top of a post in Kensington Gardens, 

 moving rapidly along with its antennae bent in the 

 form of an arch, and kept in a strong vibratory mo- 

 tion, and which the Pimpla introduced into a hole 

 made by some insect. In this situation it remained 

 for a minute, and then withdrew them, and going to 

 the opposite side it again repeated this proceeding, 

 which was a third time repeated at the side of the 

 hole. Having again drawn out its antennae, it turned 

 about, and dexterously measuring a proper distance, 

 threw back its abdomen over its head and thorax, 

 lowering the long and slender ovipositor which it 

 introduced into the hole, remaining in this situation 

 two minutes ; it then withdrew its ovipositor, turned 

 round, and again applied its antennae to the hole as 

 before, and again inserted its ovipositor, repeating 



cases of the ovipositor were also projected over the 

 back, with the ends appearing above the head out of 

 the hole. The Pimpla, indeed, docs not adopt indis- 

 criminately any hole for the reception of her eggs, 

 since Mr. Marsham observed that in many instances 

 he saw it thrust the antennae into holes and crevices 

 from which it almost immediately withdrew them, 

 and proceeded in search of others ; it is, therefore, 

 only in such holes that are inhabited by the insects 

 which are the genuine receptacles of the eggs of the 

 parasite, that the Pimpla selects for the deposition of 

 her eggs ; and that this information is obtained through 

 the medium of the antennae, appears certain, but in 

 what manner, and whether by the sense of smelling, 

 or hearing, or feeling, we can by no means decide. 



Pimpla manifestator engaged in oviposition. 



In the insect whose proceedings we have thua de- 

 tailed, we have seen that in consequence of the deep 

 retreats in which the young of the bees are lodged, it 

 is necessary that the Ichneumons, which are destined 

 to keep them in check, should be provided with an 



the operation three times. On another occasion, ovipositor sufficiently long to reach them in their cells ; 



Mr. Marsham observed several of these insects at ! but other species which have no di 



work, but these appeared to pierce the solid wood | kind to contend against, are provided wii 



with the central part of their ovipositors, which they I short ovipositor, whereby they are enabled to pene- 



succeeded in doing to half their entire length, con- trate the soft and naked bodies ot caterpillars. 



stantly supporting them in a straight position with have already in onr account of the family, 01 >re 



their posterior thighs. It appeared truly surprising properly sub-family, Bracomdes given an account c 



to see an instrument, apparently so weak and slender, | the proceedings of some of ^Ichneumons, win. 



able, with the strength of so small an animal, to pierce parasitic upon the plant lice. Mr. Kirby hi 



solid wood half or three quarters of an inch deep ; an account of one of the species which is eminently 



but it was perceived that the operation took place serviceable in keeping in check the 1 



through the centre of a small white spot, resembling domyia), which attacks the wheat wne 



