On Subaquatic Insects. 131 



The pupae (Fig. 3 and 3 a) are small, broadly ovate, flattened, 

 with the head concealed beneath the shield-like prothorax ; the an- 

 tennae cases short ; the legs arranged on the breast, not extending 

 beyond the centre of the under side of the abdomen. The wing- 

 cases are very short, not extending beyond the sides of the body ; 

 the front margin of the prothorax is furnished with two very long 

 curved and several shorter bristles. The sides of the abdominal 

 segments are also furnished with very long curved bristles, and this 

 part of the body is terminated by two minute and narrow lobes. 



It is unquestionable that both these larvae and pupee are those of 

 a species of Staphylinidse. The similarity of the former with the 

 larvae of several species of this family figured by myself in the Zoo- 

 logical Journal, and by Mr Waterhouse in the Transactions of the 

 Entomological Society, Vol. i. leaves no doubt that this is the case 

 with respect to the larva, whilst the minute size of the elytra and 

 the shortness of the antennae in the pupa, also prove that this is also 

 brachelytrous. Hence I feel but little hesitation in regarding these 

 larvae and pupae as those of Micralymma Johnstonis. In all these 

 insects we see the same provision made for occasional respiration and 

 abode beneath the surface of the water. The long hairs with which 

 the legs of the imago are furnished, and the strength of the organs 

 of the mouth, are analogous to what has been noticed in iEpus, whilst 

 a reference to the figures, both of the larvae and pupae, will show 

 that the same circumstances exist also in those states. 



There still remain to be noticed some coleopterous insects, which, 

 although unable to swim, reside at great depths beneath the surface 

 of the water, although unprovided with the long hairs which we 

 have seen are of so much service in Aepus, &c. in retaining the glo- 

 bule of air. To these M. Audouin appears at first to have been 

 inclined to apply the theory of M. Dutrochet, observing, " Je citerai 

 encore plusieurs especes de Coleopteres du genre Elmis, que Ton 

 trouve sous les pierres au fond des ruisseaux et que jamais on n'a 

 vu respirer 1'air a leur surface. II en est (a) de me?ne des Dryops 

 des Macroniques et des Georisses qui appartiennent a le meme famil- 

 le." It appears, however, that, in printing this memoir, the words 

 " a quelques egards" were omitted at the place where I have placed 

 (a). In the copy of this memoir, which the author was so kind as 

 to send me shortly after it was printed, the equivalent words " a 

 peu pres" were introduced with a pen. This is the more requisite 

 to be noticed, because my friend, M. Wesmael of Brussels, has at- 

 tacked M. Audouin upon this point, observing, that, as the surface 

 of the body in Elmis is unfurnished with long hairs, it is unable to 

 retain a bubble of air, whilst on the underside there is observed on 



