British Species of Caddis-fties. 101 
Genus Leptocerus, Leach. 
Antennz very long, twice or more than twice the length of the 
wings, shorter in the females, very thin, the joints long; basal joint 
as long as the head, bulbous. Head transverse. Maxillary palpi 
very long and hairy; basal joint short; second and third very 
Jong; fourth and fifth shorter, equal. Labial palpi small, with 
the joints nearly equal, the second stouter. Prothorax very small 
and densely hairy. Mesothorax rather large and elongate. An- 
terior wings long and narrow, slightly dilated towards the ellip- 
tical apex, costal margin straight, dorsal margin slightly concave 5 
hairy covering dense; neuration usually indistinct ; radius scarcely 
bent before the termination; discoidal cell very long and narrow, 
closed, connected with the radius by a transverse vein; the anasto- 
mosis usually oblique; first apical cell never reaching the anasto- 
mosis; in the males the anterior branch of the ramus thyrifer is 
simply forked, in the females it is twice forked. Posterior wings 
much shorter than the anterior, folded, subtriangular; discoidal cell 
open (sometimes aberrantly closed) ; fringes short. Legs short ; 
all the tibize furnished with a pair of apical spurs only, those on the 
anterior tibiae very short. Abdomen subcylindrical. In the male 
the appendices are very complicated; there is generally a bifid 
lobe from the upper margin of the last segment, beneath which, 
on either side, are seen the app. sup., which vary considerably 
in different species, but are usually straight and finger-shaped ; 
the app. inf. are long and curved, usually claw-shaped, and per- 
haps bisarticulate; the penis probably has always a projecting 
superior cover and sheaths. In the female the most prominent 
appendices are two lateral valves. 
Female generally smaller than the male. 
Larve inhabiting standing and running waters, Head small 
and much elongated. Pronotum small. Mesonotum and meta- 
notum broad. Anterior and intermediate legs rather short, the 
joints slightly dilated; posterior legs very long. Abdomen sub- 
cylindrical, the sides nearly parallel; the first segment with a 
large median dorsal hump, the lateral humps very small. 
Case a cylindrical tube of fine sand, larger at one end, generally 
more or less curved, and sometimes with vegetable débris affixed 
outside. 
The species of the elegant insects which constitute this genus 
are rather numerous and difficult to separate, owing to the fact that 
many of them vary considerably in colour and markings. The most 
certain characters are to be found in the anal appendices of the 
