158 NATURAL HISTORY OF AQUATIC INSECTS CH. 



sixth segment, and there are five segments on either 

 side of it, but as the five segments towards the tail 

 are longer than the five next to the head, the body 

 is not bent exactly in the middle. The larva keeps 

 close to the edge of still water. Only the head, the 

 tail, and the segment "next to the tail, he says, are 

 constantly in the water. He observed that when the 

 larva was attached to the side of a vessel, only the 

 head and tail being in the water, if he inclined 

 the vessel so as to cause the water to rise towards 

 the larva, it immediately crept a little higher. If the 

 vessel was inclined the opposite way, so that the larva 

 was left dry, it made haste to regain the water. 

 When creeping, the middle of the body moved fore- 

 most. The larva was provided with legs, though 

 they were too small to be seen properly with a 

 magnifying glass. The legs, he says, are attached 

 to the back, and the Insect always lies on its back, 

 with the mouth turned upwards. The legs were 

 short, and resembled the prolegs of a Silkworm, 

 being terminated bv hooks. The first four le^s were 



O J O 



directed towards the head, the others towards the 

 tail. Since the animal is bent double, all its legs 

 point the same way, and combine to propel the body 

 with the sixth segment foremost. The larva could 

 work its legs, not only from front to back, but also 

 from side to side. When submerged, it extended its 

 body, and swam like a worm. It appeared never to 

 venture into deep water voluntarily, but to regain 

 the shore as soon as possible. The mouth was 

 surrounded by prominences and tufts, which were 

 incessantly drawing water into the mouth, and thus 



