INSECTS. 229 



tie air ; and when they go to sleep for the winter they 

 require none, and their breathing stops. 



392. Some insects live on the juices of plants and of 

 animals, and some devour the substance of either the 

 one or the other. The former suck their food ; the lat- 

 ter gnaw it. These two classes, therefore, have two dif 

 ferent kinds of mouths. The gnawers, such as Beetles, 

 Cockroaches, Locusts, etc., have a complicated apparatus, 

 which I will describe. First, there are two tooth or 

 claw-like appendages, called mandibles ? these are the 

 upper jaws, which divide the food. They come together 

 by a lateral or sidewise motion. Sometimes they have 

 sharp edges to cut like scissors, and sometimes they have 

 points for tearing. Below or behind these are two other 

 jaws, called maxillce, which are very complex in their 

 structure. Above, or, rather, in front of the mandibles, 

 is a lip, and so there is one behind the maxillae. Insects 

 furnished with an apparatus of this kind are called man* 

 dibulate. 



393. In some insects we have an arrangement entirely 

 of a different character, as in the Butterfly tribe. Here 

 there is a tubular appendage, or trunk, often quite long. 



This is ordinarily coiled up, as you see 

 in Fig. 179. When the animal wishes, 

 it can uncoil it and extend it down 

 into the bosom of flowers. Such in- 

 sects are called Haustellate, from 

 h&ustellum, a sucker. This tube, or 

 Fig. 1T9. proboscis, varies much in different in- 



sects. In some, as the Bees, there is a mixture of the 

 rnandibulate and the haustellate arrangements. They 

 obtain their food by suction, and use their mandibles 

 and maxillae as trowels and spades, and knives and scis- 

 sors, in building their curious habitations. In insects 

 that suck the blood of ammals, such as the Musquito 

 and the Horsefly, there is a peculiar modification of the 

 apparatus. There is a proboscis with lancets to make 



