136 
NEUROPTERA. 
long telescopic tail process with the spiracles at the apex ; the pupa is 
propneustic with the spiracle on the tubular filaments. It is known that 
some Acalypirate muscidce have aquatic larvae, Dasycerides, Ep hydrides 
and Sciomyzides being thus found. 
The above includes the majority of: the forms with aquatic nymphs 
or larvae, but we may remember that in almost any tank or stream there 
are abundant new forms as yet unreared, and that aquatic insects are 
by no means well known. We are familiar with many fresh-water larvae 
which do not come into any of the above groups, and the Indian aquatic 
fauna is almost unknown. 
The following Hemiptera are aquatic in all stages, but all are holop- 
neustic or peripneustic. The Hebrides are scarcely truly aquatic, living 
in damp situations, the body beneath densely pubescent. Hydrometridce 
live on the surface of the water, being also pubescent below. The divi¬ 
sion Cryptocerata are aquatic, living below the surface but being holop- 
neustic or peripneustic in all stages ; Pelogonidee (Galgulidce) are alone 
found on wet mud and near water. Nepidce live in shallow water and 
obtain air by means of two processes which unite to form a slender tube; 
the nymph obtains air by means of two ventral pubescent grooves 
leading to the apex of a short process. Naucoridee carry air down with 
them in a bubble attached to the hind end and come to the surface to 
renew it ; Belostomidce are also aquatic and obtain air from the surface. 
Notonectidce and Corixidce carry air on the lower side of the body and 
come to the surface to renew it. 
So far as we are aware, there remains only one aquatic Hemipterous 
insect, an Aphid ( Rhopalosiphum nymphece Fabr.) found in India 
below the surface of fresh water on an aquatic plant. 
In the above aquatic insects, we have indicated the fact that the 
actual habitat in the water may be very different, and it will be useful 
to briefly note the habitat conditions that we find. There are many 
forms which never or only exceptionally leave the surface, such as the 
Gyrinid beetles, the larvae of Dixa and Anopheles and the various Hy¬ 
drometridce; they are aquatic only in the ^ense that they live on water 
and are adapted thereto. 
Others live near the surface and always within reach for air-getting 
purposes. Of these some live in algae or weed masses as Palustra larvae, 
the pupae of aquatic Tipulids , the larva of Stratiomys and the larva and 
pupa of Psychodidce ; others are in mud at the margin, as Ptychoptera 
and Bittacomorpha, the Tabanid larvae, the larva and pupa of the Eris- 
talis and Helophilus sections of Syrphidce. 
A number are dependent on the surface, but go deep in search of 
food or shelter ; such are the predaceous beetles (Dytiscidce and the like), 
the Hydrophilus beetles, the aquatic Cryptocerata, as well as the Culicidce 
and Dixidce. 
