120 MODERN CLASSIFICATION OF INSECTS. 



domen, which the lattei* considers serves to enable the insect to raise 

 itself to the surface of the water, and descend to the bottom. The 

 eggs are deposited in regular and transverse series upon floating 

 wood, to which they are fixed by a glutinous substance. M. Contarini 

 merely observes of their larva, that they bend themselves into a 

 curved position, and resemble those of the Melolontha ; they live 

 under the bark of the floating wood. Like the Elmis, the perfect in- 

 sects are unable to swim. Dr. Germar has described a second Eu- 

 ropean species, Parnus obscurus Fah., Germ. Ins. Nov. Sp. i. 89. ; 

 and Sturm has figured an insect from North America as a species, 

 M. variegatus, in his Catalocj. (Nurmb. 1826) ; but tlie regular struc- 

 ture of its 11-jointed antennas indicates a much nearer affinity with 

 Elmis. 



The three following families of Philhydridous Rypophaga are 

 much more intimately allied together than they are to the preceding 

 families. They correspond with Latreille's tribe of Palpicornes, and 

 have the maxillary palpi generally very greatly elongated ; the legs 

 are generally formed for swimming, although the motions of the in- 

 sects are much less active than those of the Dyticidae. Of these in- 

 sects the Helophoridae approach nearest to the preceding families ; 

 hence the transition is easy to the large typical Hydrophilidae, from 

 which, by means of some of the minute species Hydrobius, <S:c. (es- 

 pecially Coelostoma orbicularis Bridle, which has been always consi- 

 dered as one of the Hydrophilidae), we arrive at the Sphaeridiidae, 

 which, according to the views of MacLeay and others, are related to 

 the Anistomidae, although their affinity to the stercorarious Lamelli- 

 corns appears equally strong. 



The third family Helophorid^ * MacLeay (Helophoridea Leach) 

 is distinguished by having the body more or less oblong-ovate, and de- 



* BiBLioGR. References to the Helophorid^. 

 Leach. On the Helophoridea, Zool. Misc. vol. iii. 

 nUger. Kafer Preussens. 

 Gyllenhall. Ins. Suec. 

 Weber. Beytrage zur Naturk, vol. ii. 

 Sai/, in Journ. Acad. Sc. Philad. vol. iii. 



