BAKER : HYDROBIUS FUSCIPES. 331 
remainder, who had served for nourishment for the survivors. 
n colour these larve are a dirty white with the head and 
prothorax fuscous. The whole upper surface is densely covered 
with hairs and spines, and the under surface is covered in a similar 
manner, but not so thickly placed. In addition to these spines, 
which are evidently protective, each abdominal segment has about 
four tubercles, the functions of which I am unable to imagine. 
The head is small, but well armed; two sickle-shaped mandibles, 
each with three teeth in the centre, form their principal means of 
attack or defence. The maxillz consist of a large basal joint, with 
four large spines pointing inwards, and isolated ones pointing in 
other directions. On the top of the joint are four much smaller 
ones, the one next to the basal having a small tubercle at the apex. 
The labial palpi are two in number, each consisting of a small basal 
and a long apical joint. A rudimentary third palp lies between the 
two. The labrum is serrated. The antenne are three-jointed, the 
basal joint being as large as the other two together. The eyes are 
twelve in number, six on either side. The prothorax has the scutum 
entire, whereas in the meso- and meta-thorax the scuta are broken 
up, and lose the usual form entirely on the abdominal segments, 
being very much wrinkled and crossed by deep furrows. The eighth 
abdominal segment bears a sort 
of rosette of prominences which 
are capable of being shut up like a 
book (Fig. 4), or expanded at right 
angles to the body (Fig. 5); forming 
the means by which the larva is 
able to suspend itself on the surface 
film. In the centre of these are 
situated the two spiracular aper- 
tures. Air is conveyed from these 
two openings by means of two 
lateral tracheal trunks which give 
off smaller branches to the different 
parts of the body and head. 
The nervous system (Fig. 6) 
consists of a fused mass in the head 
encircling the vesophagus and giving 
ff 
e Fig. 6. 
. . ‘ . Nerv syst 
maxillz, and the labial palpi. Nerves “x6” 
Fig. 6. 
Respiratory system. 
x6. 
Nov. 1894. 
