CLASSIFICATION AND ORIGIN OF INSECTS 1401 



ing the coasts of the Scychelle Islands. The under 

 surface of the shell, instead of being gently concave, 

 as in land tortoises, has a deep circular concavity in 

 the centre, above four inches in depth, which, when 

 the animal goes into the water, retains a large vol- 

 ume of air, buoying up the whole mass while it re- 

 mains in that element. The greater size of turtles, 

 when compared with tortoises, is a further instance 

 of the superior facility with which organic growth 

 proceeds in aquatic than in land animals formed on 

 the same model of construction. 



THE CLASSIFICATION AND ORI- 

 GIN OF INSECTS. LORD AVEBURY 



ABOUT sixty years ago the civil and ecclesiasti- 

 cal authorities of St. Fernando in Chili ar- 

 rested a certain M. Renous on a charge of witchcraft 

 because he kept some caterpillars which turned into 

 butterflies. This was no doubt an extreme case of 

 ignorance; it is now almost universally known that 

 the great majority of insects quit the egg in a state 

 very different from that which they ultimately as- 

 sume; and the general statement in works on ento- 

 mology has been that the life of an insect may be 

 divided into four periods. 



Thus, according to Kirby and Spence, "the states 

 through which the insects pass are four: the egg, the 

 larva, the pupa, and the imago" Burmeister, also, 

 says that, excluding certain very rare anomalies, "we 

 may observe four distinct periods of existence in 

 every insect namely, those of the egg, the larva, 



