CHALCIDID.E. 



[ 158 ] 



CHALCIDID.E. 



tinuous with the coats, and where the vas- 

 cular cord derived from the placenta termi- 

 nates (fig. 116, ch). 



CHALCID'ID^E. A family of Entomo- 

 phagous Terebrant Hymenoptera, distin- 

 guished by the following characters : 



Head transverse, with the eves lateral 

 and the face usually bisulcate for the re- 

 ception of the base of the antennas (PI. 36. 

 fig. 8). Antennae short, frequently thick- 

 ened at the tips, sometimes branched, com- 

 posed of not more than thirteen joints, 

 and almost always geniculated at the ex- 

 tremity of the elongated first joint. Palpi 

 very short, sometimes branched. Thorax 

 ovate, with a distinct collar. Wings nearly 

 destitute of veins ; the anterior with a rather 

 strong subcostal vein running parallel to the 

 anterior margin for about half the length of 

 the wing, and terminating in a stigma, from 

 which a short vein is given off obliquely 

 towards the disk of the wing ; the posterior 

 sometimes veinless, sometimes with a short 

 subcostal vein. Legs moderate; hinder 

 thighs sometimes much thickened ; tarsi of 

 four or five joints. Abdomen generally com- 

 posed of seven segments in the males and of 

 six in the females, united to the thorax by 

 a peduncle of variable length ; ovipositor 

 usually concealed entirely in a cleft of the 

 lower surface of the abdomen, which ex- 

 tends nearly to the base (fig. 9), but some- 

 times exserted and very long. The struc- 

 ture of the ovipositor is the same as that of 

 the IchneumonidcR. 



The larvae, like those of the rest of the 

 petiolated Hvmenoptera, are footless fleshy 

 grubs (fig. 10). Like the larvae of the Ichneu- 

 monidae, they usually live in the interior of 

 other insects ; but it is remarkable that those 

 of a few species attach themselves to the 

 skin of their victim, and in this position 

 feed upon its substance. The internal 

 feeders generally change to the pupa state 

 within the pupa of the insect attacked by 

 them ; a few, however, break through the 

 skin of the larva and attach themselves to it 

 or to neighbouring objects by a glutinous 

 secretion, or by a small silken cocoon. The 

 pupa? have the limbs more closely attached 

 to the body than in the other Hymenoptera; 

 and in those which have an elongated ovi- 

 positor, that organ is turned up over the 

 back. The pupae are at first whitish, but 

 afterwards become brown or black ; they 

 are usually naked (fig. 11). 



The family Chalcididae includes an im- 

 mense number of parasitic Hymenoptera, 



the majority of which are of extremely mi- 

 nute size, and adorned with the most bril- 

 liant metallic colours. This circumstance, 

 coupled with the delicacy of their form, 

 renders many of the species most beautiful 

 objects; and considering their interesting 

 habits, they certainly do not deserve the 

 almost total neglect which they have met 

 with. The largest species belong to the 

 genus Leucopsis ; but none of these greatly 

 exceed half an inch in length, and they are 

 not found further north than the South 

 of Europe. The thickened hinder thighs 

 which occur in manjr species of this fa- 

 mily, do not always indicate that the in- 

 sects possessing them are endowed with 

 saltatorial powers ; on the other hand, many 

 species which are destitute of thickened 

 thighs leap well ; and according to West- 

 wood's observations, this is especially the 

 case with those in which the intermediate 

 tibiae are furnished with a large spine at 

 the extremity (Encyrtut, PI. 36. fig. 12). 



The perfect insects may be met with in 

 abundance during the summer and autumn 

 upon the leaves of trees and plants. They 

 may be taken either by sweeping the herb- 

 age with a net, or by beating trees or hedges 

 over a broad net or umbrella. 



The sexes are often distinguished in this 

 family by remarkable external characters, 

 especially in the structure of the antennae. 

 These, in the males of many species, are 

 beautifully branched, in consequence of the 

 joints giving off processes from their sides ; 

 in Eulophus (fig. 13) we usually find three 

 branches ; and in some foreign genera re- 

 corded by Westwood the number is in- 

 creased to five, seven, and even nine. A 

 few species have the wings rudimentary or 

 entirely wanting ; and it is remarkable that 

 in some cases the male only is deprived of 

 wings, the female being well furnished with 

 these organs. 



The Chalcididae are parasitic upon insects 

 of nearly all orders, and deposit their eggs 

 in them in all stages of their growth. Some 

 of the minute species even find sufficient 

 nourishment in the eggs of other insects ; 

 amongst these we may mention Pteromalus 

 ovulorum as a common species, which has 

 been reared from the eggs of Lepidopterous 

 insects. From a single egg of this descrip- 

 tion, Fonscolornbe obtained five or six indi- 

 viduals of a minute species, described by 

 him under the name of Pteromalus atomos. 

 Westwood also mentions the occurrence of 

 two species of this family in the egg-cases 



