30 



SOME SOUTH INDIAN INSECTS, ETC. [("HAP. HI 



A typical larva may be considered as long and cylindrical, 

 somewhat flattened along the ventral surface, and composed of 

 about fifteen segments or rings between each of which the body is 

 more or less constricted transversely. The first segment is the head. 

 itself composed of four or more sub-segments fused together and not 

 distinguishable after hatching, and this is a more or les- chitinous 

 (horny) oval case carrying the mouth with its appendages and (in 

 free-living forms) a small number of ocelli arranged in lunular form 

 on each cheek. The second, third and fourth segments (corre- 

 sponding to the pro-, meso-, and meta-thoracic segments of the 

 adult insect) each carry a pair of more or less hornj legs which 

 terminate' each in a single claw. The fifth to fifteenth segments 

 (of which, however, two or more are usually fused together) corre- 

 spond to the abdomen or body of the adult insect and in free-living 

 forms may carry a variable number of pro-legs which are generally 

 present in the Lepidoptera (not more than five pairs), rarely present 

 in thi' Hymenoptera (Saw-flies, more than five pairs) and absent 

 in the other Orders. Breathing is provided for by a tracheal system 

 communicating with the open air by means of spiracles which are 

 small round openings found on each side of the second and fifth to 

 twelfth segments in lepidopterous larvae but in some larvae 

 (especially some of the dipterous larvae) the breathing system is 

 very greath modified. Larvae living a concealed existence are 

 usually whitish in colour, occasionally reddish, those living an 

 active exposed existence are often highly procrypticall y coloured 

 or show vivid warning coloration. The larva, when full-fed, casts 

 its skin for the last time and changes into a pupa in which stage it 

 is inactive and motionless except for wriggling or occasional 



jumping mot ements). In 

 the more generalized 

 groups ot the Lepido] 

 and generallj in the 

 Coleoptera ami Hymenop- 

 tera the limbs of the 

 future perfect insect are 

 more or le^s separate, 

 each encased in its own 

 pupal sheath, but in the 

 more specialized groups 

 of the Lepidoptera and 

 in the Diptera the ap- 

 pendage sheaths a; 

 to speak) soldered into the rigid, smooth, uniform pupal -.hell. 

 In all the holometabolic insects the cocoon-making instinct is 



I n,. 15. Pupa "i Orneodes hexadactyla, 

 :i Lepidopti '. showing ventral, 



lateral, and d ipman.) 



