298 Bibliographical 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 superfiuous, 
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 larve belong? And a few leading results may 
easily be pointed out. The new division of the family of Carabi, 
proposed by Prof. Schiddte 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 antenne &c., is fully borne out by 
the larve, particularly the union of Carabini, Elaphrini, and the 
anomalous genus Loricera, 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 larve possess true, almost invariably double, claws, 
with proper apparatus of muscles, whilst the larvee of all other fami- 
lies have only a “tarsus unguiformis.” The union of Silphe and 
Anisotome is also strongly supported by the similarity of the larve; 
and the received division of Dytisci and Hydrophili into groups is like- 
wise most markedly expressed in the larve. The larve of Haliplini 
are distinguished from those of the other groups not only by their 
dorsai segments being armed with spines, which gives them avery ~ 
grotesque appearance, but by their possessing only one claw, whilst 
all others have two, and by their anal segment (which is rudimen- 
tary in all other Dytisci) being enormously elongated and bifurcate, 
so that the anus is placed on the underside 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 larve 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) ciliated legs. Then follow the well-known 
larger larve of Dytiscus, 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 larve of Helophorus (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 covering which enables the larvae of Hydre- 
philus and others to carry with them a supply of air surrounding their 
