128 COLBOPTERA OR BEETLES. 



COLEOPTERA, 



OR Beetles. 



The Coleoptera or Beetles are characterised hy possessing four 

 wings. The front pair are horny, and are called elytra ; they 

 close over and protect the second pair, which are folded up. 

 The elytra meet in a straight line (suture) down the middle of 

 the abdomen. The larvae of Coleoptera are of two main types 

 — one typically represented hy the wire worm (fig. 62), in which 

 the first three segments have each a pair of jointed legs; the 

 other by the maggot-like grubs of the weevils (fig. 57), which 

 are footless, and usually more or less curved. The body is com- 

 posed of thirteen segments, including the head. Many, such as 

 the Gic.indelidce, have peculiar organs for catching their prey. 

 The pupse are always inactive. The larvse feed upon animal 

 life (carnivorous) or vegetable life, and may even be parasitic, as 

 in the Stylopidce found on bees : many also feed upon decaying 

 matter, acting as scavengers {Necropliagi or Burying Beetles). 

 The pupae are sometimes enclosed in a cocoon, the parts of the 

 insect being always distinctly recognisable. 



In structure the beetles have the following peculiarities : 

 The mouth consists of an upper lip or labrum, two mandibles, 

 which are hard and horny, two maxillfe with palps, which are 

 generally four-jointed, and a movable lower lip or labium, with 

 two -jointed labial palpi. The antennte are very variable, 

 generally composed of eleven joints. The pro-, meso-, and meta- 

 thorax are all well developed ; but when the elytra are closed, 

 only the prothorax is seen, and a small part of the mesothorax 

 called the ■■^ruteUum, which fits between the elytra at their 

 base. The tarsus may have five, four, or three joints, but 

 never more than five, the last joint ending in two ungues or 

 claws. 



The number of tarsal joints has been made a basis for classi- 



