INSECT LIFE IN INDIA AND HOW TO STUDY IT. 173 



'the bugs' (Hemiptera). Here we have a jointed beak or rostrum, 

 instead of the long tube, made up of four segments, inside which run 

 four pointed lancets. This is used first for piercing plant structures, &c, 

 and then for sucking up their juices. Insects with this form of mouth 

 cannot be reached by internal poisons. The Flies (Diptera), have a 

 modification of this form of mouth, the piercing organs being at times 

 absent as in the house fly. Occasionally the mouth is both biting and 

 sucking as in the bees, the mandibles being fully developed and the labium 

 greatly elongated to enable the insects to gather the nectar upon which 

 they feed. The head also bears the eyes, which may be compound, com- 

 posed of a large number of facets, or simple (ocelli), and the antennae, con- 

 sisting of a number of joints (see Fig. 4). The thorax, which comes behind 

 the head, is divided into three portions — the pro-thorax, bearing the first 

 pair of legs, the meso-thorax, bearing the second pair of legs and the 

 c first pair of wings (if present), and the meta- 



f thorax, bearing the third pair of legs and 



» the second pair of wings (if present). 

 Behind the thorax comes the abdomen, 

 consisting usually of ten sograents, though 

 fewer may be visible, which are usually 

 freely movable upon one another and never 

 carry locomotion limbs. The extremity of 

 r the abdomen is, however, often furnished 

 with appendages, which are primarily con- 

 nected with reproduction, but which are 

 FIG. 4.— Front view of head . 



of a cricket iBrachptrupes often converted into weapons of offence and 



achoetinus). a. epicranium ; b, defence. Of such a nature are the oviposi- 

 compound eye;,, antenna; d '. .^ of Ichneumons the stings of bees, 

 elypeus ; e, labrum ; /, base ot m 



mandible ; g, palpi. wasps, &c. The leg is divided into several 



joints— the 'coxa,' the joint of attachment to the body, the ' trochanter,' 



a short joint following the coxa, the femur (or thigh), the tibia (or 



shank), and the tarsus, composed of a number of joints, from one 



to five in number ; following the tarsus there may be a claw 



(see Fig. 2). 



Classification. 



It has already been stated that insects are the most numerous in 



species and individuals of all land animals. It is estimated that 



somewhere about 255,000 species have been already described and this is 



probably but a tenth of those that really exist. 



