INSECTS : THEIR BEEATHTNG OEGAUS. 115 



length, tluckest a little behind the head, and tapering 

 gradually to a lengthened tail, the twelve segments of 

 the body being very conspicuous. It swims up and 

 down or to and fro in the clear water, with a not 

 very rapid, wriggling movement, throwing its body 

 alternately from side to side in the form of the let- 

 ter S. 



This is the maggot of a handsome dipterous fly, 

 sometimes called the Chameleon-fly {SPratioTnys cham- 

 celeon). There is much about it to reward observation 

 and careful examination with a low magnifying power, 

 especially the head, with its pointed snout, and its pair 

 of foot-like palpi. These are situated one on each side 

 of the head, are three-jointed, the last joint being 

 studded with short stiff spines, and the second having a 

 thumb-like projection. With these organs, the grub 

 roots and burrows among the decaying vegetable mat- 

 ter at the bottom for its food ; and when not so engaged, 

 they are often rapidly vibrated in a singular manner, 

 the sight of which might induce a feeling of fear, as if 

 they-were threatening weapons of offence, — a pair of 

 poisonous stings, for instance ; they have, however, 

 no such function, the poor grub being perfectly harm- 

 less. 



What I wish you chiefly to observe, however, is the 

 tail, with its curious organization. With the naked 

 eye, you can perceive that the last joint is much slend- 

 erer and more lengthened than the rest, and that it is 

 tipped with a beautiful crown of feathers, like the 

 diadem of some semi-savage prince. This is best seen 

 when the animal comes to the surface, which it always 

 does tail uppermost, for as soon as the tip reaches 

 the air, the plumes instantly open, and form an ex- 



