298 BibUographical Notices. 



and illustration. Almost everything in this memoir is therefore 

 new ; and it would be so much the more difficult to make a suitable 

 extract from the host of new observations, as, in spite of the great 

 mass of detail, nothing has been included in the descriptions but 

 what really has scientific value. It is an exceedingly difficult task, 

 in commencing the study of a new branch, to limit properly the 

 detail to be inserted in the descriptions, because experience alone 

 can show what has systematic and philosophical value, and what not. 

 But in the memoir before us the matter seems to have been prepared 

 so long and weighed so carefully that there is nothing superfluous, 

 nothing that does not really serve to complete our conception of the 

 animals. One question, however, may fairly be asked, viz., "What 

 light do these investigations throw on the systematic relations of the 

 families to which the larvae belong ? And a few leading results may 

 easily be pointed out. The new division of the famUy of Carabi, 

 proposed by Prof. Schiodte some years ago (Ann. Nat. Hist. ser. 3. 

 vol. X. p. 380), and based on the development of the epimera meta- 

 thoracica and the position of the antennae &c., is fully borne out by 

 the larvae, particiilarly the union of Carabini, Elaphrini, and the 

 anomalous genus Lorkera, Latr., into one natural group. The close 

 relationship of Carabi, Dytisci, and Gyrini, which form such a well- 

 defined group at the head of the order, finds an expression in the 

 fact that their larvae possess true, almost invariably double, claws, 

 with proper apparatus of muscles, whilst the larvae of all other fami- 

 lies have only a *' tarsus unguiformis." The union of Silphae and 

 Anisotomae is also strongly supported by the similarity of the larvae; 

 and the received division of Dytisci and Hydrophili into groups is like- 

 wise most markedly expressed in the larvae. The larvae of Haliplini 

 are distinguished from those of the other groups not only by their 

 dorsal segments being armed with spines, which gives them a very 

 grotesque appearance, biit by their possessing only one claw, whilst 

 all others have two, and by their anal segment (which is rudimen- 

 tary in aU other Dytisci) being enormously elongated and bifurcate, 

 so that the anus is placed on the imderside of this peculiar tail, and 

 the spiracles of the eighth pair, which are terminal and tubiform in 

 other Dytisci, here become lateral and quite plain. The larvae of 

 Hydroporini are all distinguished by the production of their fore- 

 head so as to form a kind of horn, against the under surface of which 

 the mandibles, being very long and curved upwards, work, whereby 

 they are enabled to keep their prey very firm while sucking it out ; 

 they are also swift swimmers, thanks to the shape of their body 

 and their (usually) cUiated legs. Then foUow the well-known 

 larger larvae of Dytisms, with large, free, round heads, narrow 

 prothorax forming a kind of neck, and ciliated abdomen. Still 

 greater variety is met with amongst Hydrophili, beginning with 

 the amphibious larvae of HeJopliorus (which catch their prey run- 

 ning), whose lateral abdominal appendages are stiff and adapted for 

 supporting their crawling movements, and who are also destitute of 

 the peculiar hairy or felty covex'ing which enables the larvae of Hydro- 

 philus and others to carry with them a supply of air surrounding their 



