INSECT LIFE IN INDIA. 425 



The beetles are one of the largest and most important of the Orders 

 of Insects as well as being one of the most injurious both in the field 

 a,nd forest. Both larvae and mature insects bore into vegetable sub- 

 stances of all kinds affecting and often destroying the roots, stems, 

 flowers and seeds of plants. 



Beetles are chiefly distinguished from other Insects by the solidarity 

 of their outer covering and by the peculiar nature of their first pair of 

 wings, which are not used as instruments of flight, but merely serve to 

 protect the hinder part of the body. Beetles are not found on the wing 

 as much as other Insects, and therefore, notwithstanding their enormous 

 numbers, they are not met with so frequently as ants, bees, flies, etc. , 

 The number of species at present known is probably about 160,000, or 

 thereabouts, and their habits are so varied that they can be found 

 everywhere when looked for. The general form varies much from flat- 

 spherical to long-linear. The head is well developed, with a biting 

 mouth ; compound eyes are present, which are not uncommonly divided. 

 Ocelli (simple eyes) are rare. Antennae eleven-jointed or with fewer 

 joints. These latter are variable in shape and are of importance in 

 classification. The structure of the hard parts of the skeleton is of 

 importance since the classification of the species is entirely based upon 

 it. The pro-thorax is very free and is therefore capable of a considerable 

 amount of movement independent of the after part of the body. The 

 meso-thorax is much reduced. The meta-thorax is largely developed in 

 winged forms. Fig. 88 shows the under surface of a beetle with the 

 different parts named. It is essential that the student of the Coleoptera 

 should make himself thoroughly acquainted with the nomenclature of 

 the different parts. The elytra frequently have a remarkable sculpture 

 the use of which is usually unknown. When the elytra are shut up, 

 they cover the greater part of the meso- and meta-thorax, abdomen, and 

 the lower wings. At the top there is a triangular portion called the 

 scutellum, which forms the upper part of the meso-thorax. The elytra 

 may leave a few of the lower segments of the body exposed. 



These elytra are of such importance to the beetle that they are even 

 present in cases where there are no lower wings. When this occurs 

 they are often joined together down the central suture so as io form one 

 piece, although the line representing the junction is always present. 

 When a beetle flies, the elytra open slightly upwards, letting free the 

 lower wings (vide Fig. 87), In the common rose-chafer (the green 



