BAKER : HYDROEIUS FUSCIPES. 



331 



remainder, who had served for nourishment for the survivors. 

 In colour these larvae 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 maxillae 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 antennae are three-jointed, the 

 basal joint being as large as the other two togedier. 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 ciossed by deep furrows. The eiglith 

 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 oesophagus and giving 

 ofT from the sides separate nerves 

 to each of the twelve eye spots. 

 From the anterior margin nerves 

 are given off to the antennae, the 

 maxillae, and the labial palpi. Nerves 



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K. 



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Fig. 5. 



Respiratory system. 



Fig. 6. 



Nervous system. 



Naturalist 



