234 '*' • [September 



at all. If then the young Grrasshopper, when it leaves the egg, is a 

 pupa, it will only moult once before it becomes an imago ; and if, as 

 Agassiz seems to assert, it is an imago when it leaves the egg, it will 

 not moult at all. Now what are the facts ? Westwood, the most in- 

 variably accurate of all modern entomologists, says that Orthoptera ordi- 

 narily moult six times, viz. four times in the larva state, once when 

 they pass into the pupa state, and once when they pass into the imago 

 state (Intr. I. p. 411); and this is pretty generally the rule with all 

 insects. Indeed, if they do not moult after hatching out from the 

 egg, how are they to grow ? An insect has a horny skeleton on the 

 outside to which its mu.scles are attached, just as a Crustacean has a 

 calcareous skeleton on the outside to which its muscles are attached ; 

 and neither skeleton is susceptible of gradual enlargement, like the 

 internal skeleton in Vertebrata, which is the reason of the well-known 

 fact that the Imago in insects cannot grow. Hence, instead of shed- 

 ding their flesh and sitting in their hones, as Sidney Smith proposed to 

 do in hot weather, both are compelled from time to time to shed their 

 bones and sit in their flesh, until Nature provides them with a new 

 skeleton, which in its turn will be thrown ofl' so soon as they have out- 

 grown it. 



4^/i. If the young Gras.shopper, at the moment of its exclusion from 

 the egg, was in the imago state, its reproductive system would be already 

 fully developed and active. Every field-entomologist knows that it is 

 not so, and that even with those species which in the imago have wings 

 scarcely longer, though considerably broader, than in the pupa, the 

 pupa is never found in copulation. 



On the whole, considering the enormous variation in the shape of those 

 larvae, which even Prof. Agassiz will allow to be true larva3 and not 

 mere wingless imagos, running through all the intermediate grades 

 from the short, squat, almost spherical larva of Copris Carolina ( Pror. 

 Ent. Sac. Philad., Vol. I, Plate I, fig. 1.) to the very elongated, worm- 

 like larva of most E later id ee ; and considering also how loo.se and in- 

 definite are such phrases as " worm-like," it seems rather unphilosophi- 

 cal to base a scientific theory upon so shifting a foundation. 



IV. As we have seen that Prof. iVgassiz traces a vague analogy 

 between the larva state of insects and the true Worms, so he traces 



