284 
COLEOPTERA. 
legs are slightly flattened and set with hairs, so as to render them 
capable of acting as paddles. 
The life-history of no Indian species has been worked out and 
nothing appears to be on record. The life-history of aquatic species else¬ 
where is known and the student should 
consult Miall’s ‘‘Aquatic Insects.” The 
eggs are laid in a case formed of filaments 
excreted from the silk tubes at the anus of 
the female beetle; this case is hollow and 
has a projecting process like a mast; it is 
fixed to aquatic plants at the surface of the 
water. The young are similar in general 
form to those of the Dytiscids (the tarsus 
with one claw) and also predaceous; air is 
obtained by bringing the large spiracles at 
the hind end of the body to the surface. 
Pupation takes place in the mud. The 
beetles swim actively and obtain air by 
coming to the surface head up, the air being 
contained on the lower surface of the body 
and communicating with the cavity in which 
the antenna lies; when the head comes up, the air supply is in 
contact with the atmosphere through this channel and is renewed. 
The beetles are principally vegetarian and not predaceous. Only a 
part are aquatic, some being found in mud, near streams and ponds, 
under the bark of trees and in dung. 
Fir 
160. — H Y D ROPHILTJS 
PICEUS LARVA. 
(After Chapuis.) 
The family is a moderately large one, divided into five sub-families 
as follows :— 
I. Basal joint of posterior tarsi short, second 
long. 
(a) Posterior tarsi formed for swimming. 
A sternal process present .. Hydrophilinoe . 
(aa) Posterior tarsi normal. No sternal 
process .. .. .. Hydrobiince . 
II. Four basal joints of posterior tarsi short 
and equal ., .. .. Spercheinm . 
