248 NATURAL ARRANGEMENT OF INSECTS. 



Other families of this circle we can scarcely, at present, 

 determine. [\V. E. Sh.] 



(221.) The fifth and last family of the Lamelli- 

 cornes are the aquatic beetles, forming Latreille's Hy- 

 drophylii, — a name we retain, merely giving it the family 

 termination of id(B. It is more than probable, also, that 

 Spharidium likewise enters in this part of the circle : 

 the very name of the best known type, .S'. Scarabtpoides, 

 shows its resemblance to the typical families ; while the 

 little insects forming the genera Elophorus, and two or 

 three of similar value, show the mutual connection of 

 the semi-rapacious, and therefore typical, Hydrophylidre, 

 to the other lamellicorn families, and to the predatorial 

 tribe which succeeds this. These water scarabs, never- 

 theless, are very few in number, although of a large 

 size ; they s%vim with facility, but not with swiftness. 

 One of these is a common inhabitant of the ponds and 

 fresh waters of Britain ; and others, differing nothing in 

 structure, occur within the tropics : the antennse are 

 clavate, and thus exhibit a good deal of the lamellicorn 

 type ; while in other respects they show a close relation- 

 ship to the true DytiscidcB. 



(222.) As in all other groups, we also find here, in 

 the more typical representatives, a combining character, 

 which exhibits itself in the great elongation of the 

 palpi, which, notwithstanding the differences in the 

 habits of the insects themselves, — and these are great, — 

 unite them permanently together. We find here aquatic, 

 sub-aquatic, and terrestrial forms, each displaying those 

 definite modifications which result from their appropri- 

 ation to a distinctive peculiarity. Thus, we have the na- 

 tatorial form displayed in Hydrophilus piceus, peculiarly 

 suited for progression through so dense a medium ; and 

 the proof of which we shall find in its universal occurrence 

 among the true water beetles, as we observe its analogy 

 in the form of fishes, and man's imitation of these in the 

 shapes of his ships and boats. The larva of the type 

 of this genus is remarkable for being carnivorous, 

 whereas the imago is herbivorous ; and the latter, unlike 



