Growth — Larvae 103 



skin-castings, are undergone, and in the third stage 

 (fig. 63 c) the wing-rudiments are clearly visible as 

 outgrowths from the second and third fore-body 

 segments. In the fourth and fifth stages (fig. 63 d, e) 

 these rudiments are conspicuous, and show plainly 

 the radiating nervures. A short time after the fifth 

 moult, the wings spread and harden, and the Locust 

 assumes the adult form (fig. 6^/). 



Forms of Larvae. — Most insects, however, in 

 the first period of life after hatching, differ markedly 

 from their parents in form, structure and habits. 

 From the egg of a Moth hatches out a creeping 

 Caterpillar, from that of a Fly a sluggish Maggot. 

 An animal in its early stage thus differing from its 

 parents is known as a larva, and the term is often 

 applied to insects generally as hatched from the 

 egg, though it should not be given to those which 

 differ from their parents only in size and in the 

 absence of wings ; for such the term nymph is pre- 

 ferable (2). Insect larvae show the greatest variation 

 in their form and structure. Most of them may, 

 however, be referred to one of two types. 



Campodeiform Larvae. — As an example of the 

 first type we may take the grub of a Ground-beetle. 

 It is an elongate, active creature, with a broad, quad- 

 rate head, three thoracic segments, corresponding to 

 those of the perfect insect and bearing each a pair 

 of legs and ten visible abdominal segments (fig. 64). 

 The segments of the thorax have the skin almost 

 completely chitinised. Each segment of the hind- 

 body has a single strong chitinous tergal plate, a 

 pair of pleural plates, and (as regards the first seven 

 segments) seven ventral or sternal plates. The eighth 

 segment has but three ventral plates and the ninth 

 only one, while the tenth segment is a truncated " anal 

 cylinder " (fig. 6^,^°). The head bears append- 



