270 INSECTS AT HOME. 



The head is adorned with two enormous eyes, or rather eye- 

 masses, and, during the life of the insect, the liylit plays in 

 and through these eyes in a most beautiful but quite inde- 

 scribable manner. Unfortunately, tliis play of colour and 

 liiiht fades to<>ether with the life, and, when the insect is drv, 

 it vanishes altogether. Beside the compound eyes, there are 

 three ' ocelli,' or simple eyes, placed usually in a row on the 

 front of the head. The antennae are very short and small, 

 and have never more than eight joints. The mouth is very 

 curiously formed, the mandibles and the maxillae being hidden 

 behind two large flat lips, which move up and down wliile the 

 insect is eating, so that at first sight the Dragon-fly really 

 looks as if its mouth worked vertically and not laterally. 



During its preliminary stages the Dragon-fly lives in the 

 water, and the larva is one of the most curious and interesting 

 beings which our waters produce. These larvae are so wonderful, 

 in fact, and possess so many points of interest, that I scarcely 

 know which to take first. The chief points of interest lie, 

 however, in the head and the tail, and we will give to the 

 former the place of honour. 



At first sight the head does not appear to differ very much 

 from that of other insects, but on closer examination a very 

 singular development of the mouth is shown. If the creature 

 be turned on its back, a horny plate will be seen, which covers 

 the whole of the under side of the head and descends as far as 

 the bases of the middle pair of legs. With a pin it is easy 

 to raise this plate, which then shows itself to be composed of 

 several portions and furnished with a hinge, by means of 

 which it can be doubled upon itself. The upper part, which 

 covers the face, is much widened, and is furnished with two 

 jaw-like appendages, which can be opened or closed at will, 

 and are finely toothed at their lower edges. 



This remarkable apparatus is a development of the lower lip, 

 and is called the mask, because, when closed, it covers the 

 lower part of the head. The object of the mask is to cateii 

 prey, and a very effective apparatus it is. When an iinfor- 

 tunate insect comes near, the Dragon-fly larva suddt'nly un- 

 folds its mask, darts it out to its full length, and seizes tlie 

 insect in the jaws. The mask is then closed again, and, when 

 folded, the jaws of the mask come exactly upon those of tlie 



