126 MODERN CLASSIFICATION OF INSECTS. 



the extremity of the body, and in which it undergoes its metamor- 

 phoses. The pupa is thick, and of an oval form, having two rather 

 long curved anal appendages ; the sides of the abdomen and front 

 margin of the thorax being beset with rigid hairs, which Lyonnet 

 supposed served to keep the body of the pupa from resting on the 

 damp earth. The pupae of some species are, however, destitute of 

 these spines. The larva of this insect has been figured by Mouffet 

 (p. 320.), Frisch (vol. i. pt. 2. tab. 6.), Lesser, Insecto- Theologie (vol. ii. 

 fig. 12. 16.), Lyonnet, Post. Mem. pi. 13., Audouin and Brulle (vol. v. 

 pi. 11.). It assumes the perfect state in about one hundred days from 

 the time when the eggs were hatched, of which period about sixty 

 days were occupied in the larva state. 



The larva of Hydrocharis caraboides, figured by Rosel (^Insect. 

 Belust. vol. ii., Ins. Aquat. tab. 4.), and Lyonnet* (3Iem. pi. xii. 

 fig, 'l'?. 50.), and Harris (Aurelimi, pi. 26. f. e-i), somewhat resembles 

 that of Hydrophilus piceus in its general form (^ff. 8. 13.), but is con- 

 siderably smaller ; and each of the seven basal segments of the abdo- 

 men is furnished on each side with a rather long, slender, and ciliated 

 filament, similar to the larvae of the Ephemeridse ; the terminal seg- 

 ment also bears at its extremity a pair of slender filiform appendages. 

 The pupa resembles that of the Hydrophilus ; its abdomen being ter- 

 minated by a strong pedunculated lunar-shaped process. The eggs are 

 deposited by the female in a cocoon similar to that of Hydro- 

 philus piceus. 



M. Miger (in the Annales chi Museum cV Histoire Naturelle, vol. xiv., 

 and in the Bulletin de la Soc. Philomat. 1812) has also observed 

 the larvai of other species, namely, H. luridus, fuscipes, picipes, nanus, 

 lividus, and truncatellus, belonging to the smaller genera, some of 

 which are not furnished with appendages at the extremity of the body ; 

 they are unable to swim ; neither do they suspend themselves at the 

 surface of the water for respiration, as the preceding species are com- 

 pelled to do. The female insects of these species swim also with 

 difficulty, carrying their eggs for a long time underneath their abdo- 

 men, enclosed in a silken web t, which they at length attach by gluten 



* M. Brulle (Hist, Nat. Col. vol. v. p. 256.) has erroneously supposed this figure 

 to represent a species of Philhydrus. 



f JM. V. Audouin has communicated to me the observation that the female 

 Philhydrus bicolor SoUer, carries its eggs about with it by the assistance of three 

 dilated setose appendages at the extremity of the posterior femora. 



