OF CERTAIN CHALCIDIDjE AND ICHNEUMONID^E. 69 



Of fifteen specimens allowed to complete their changes, there were only two males, with 

 thirteen females. The remaining specimens I had preserved in their larva and nymph 

 states for dissection. This small number of males coincides with the small number of 

 this sex in other bee-parasites ; but the deficiency in numbers is fully compensated for by 

 the activity of the individuals. 



The fewness of the males, and their great activity, lead me to believe that the females are 

 impregnated, not before, but shortly after they have left the cell, and in the hot sunshine. 

 Like the Chrysididce, these insects are active only in strong light. Both sexes of my speci- 

 mens always became dull and motionless when removed from the light ; but when exposed 

 to the sun they immediately resumed their activity. They seem to live but a short period in 

 the imago state. The males died within a few days, and the females in about a fortnight. 



I have proposed for this species the name of nitidus *, from its elegant and glistening 

 appearance. It may be described as follows : 



MONODONTOMERTJS NITIDUS. 



Male. — Head and thorax brilliant shagreen, with fine short hairs : head broader than the thorax, face 

 bluish; labrum emarginated ; eyes and ocelli large, dark brown; antenna? 11-jointed, basal joint 

 coppery. Prothorax compressed and slightly excavated at the sides. Metathorax and scutellum 

 large. Abdomen green bronze, hairy, petiolated, very much compressed at its base, and keeled on 

 the ventral surface ; first and second pairs of thighs green ; third pair large, copper-coloured ; tibiae 

 and tarsi fuscous, very hairy. Wings hyaline, hairy, with black costal spot. Length two lines and 

 a half. 



Female (fig. 12). — Head and thorax brilliant shagreen, hairy : head large ; face blue, punctured ; eyes and 

 ocelli large, brown; antennae pubescent, 11-jointed, with the basal joint coppery, as in the male. 

 Thorax compressed laterally. Scutellum very large. Thighs green, shining. Tibiae and tarsi hairy, 

 fuscous, with an acute spine at the articulation of the tibiae. Abdomen coppery, polished, with a few 

 white hairs, subsessile, compressed at its sides, and strongly keeled ; ovipositor exserted, longer than 

 the abdomen, and very acute. Wings dusky iridescent, hairy, and with dark marginal spot. Length 

 of body two lines f. 



From the length of the ovipositor in this insect, we may conclude that the female does 

 not enter the bees' nest to deposit her eggs ; but that she perforates the cell and conveys 

 them into it, after the cell is closed, and probably after the young bee is hatched. Every 

 part of the anatomy of this insect, as of the preceding, and of every other species when 

 attentively considered, will thus be found to exemplify its general economy, and to indi- 

 cate how closely the one is connected with the other, — how intimately associated is the 

 instinct of a living being with special conformations of its organism. Some other families 

 of Hymenopterous parasites are marked instances of the unfolding of peculiar instincts 

 subsequent to the development of particular structures. Amongst these we may notice 

 two of the true Ichneumonidte, Paniscus virgatus and Ichneumon Atropos. 



* This name was proposed for the insect at a Meeting of the Entomological Society, on the 3rd of July, 1848, and 

 the discovery of the larva in the nests of Anthophora retusa was then mentioned. See Proceedings, Ent. Soc. Trans, 

 vol. v. part 5. p. xlii. 1848. 



f Mr. Walker has recently re-described this species as " Monodontomerus Anthophorce, Newp." See Ann. and 

 Mag. of Nat. Hist. vol. ix. No. 49. Jan. 1852, p. 43. 



