"3 



tion of insects, had divided insects into 13 orders, all the principal of 

 which were the same as those before mentioned in Cuvier's arrangement, 

 with the exception of the order Hcmiptera. 



These orders had also been divided according to the nature of 

 their metamorphoses, into two groups, namely, Heteromorpha, or, as 

 Professor Westwood has described them, " those in which there is no 

 resemblance between the parent and the offspring ; and Homomorpha, 

 or those in which the larva resembles the imago except in the absence 

 of wings. In the Homomorpha (which include, amongst other orders, 

 the Orthoptera, the Hemiptera, and certain Ncuroptera) the body, 

 legs, and antennre are nearly similar in their form to those of the per- 

 fect insect, but the wings are wanting." The Homomorphic insects did 

 not pass through such distinct changes of form as the Heteromorphic, 

 and were active during all the stages of their existence (except, of 

 course, the egg state), so that, as explained, there were not, in fact, in 

 fl// orders of insects four well defined periods of existence, but in 

 many cases the progress of development towards the final stage of 

 the cycle of the insect's existence was gradual and almost imperceptible. 



The generation of an insect was the commencement of the^<?r/« 

 of its existence. After generation the subsequent life of the insect 

 consisted in development. The first state in which the insect might 

 be said to have an independent existence was the egg. The egg, 

 under the requisite conditions of light, air, and heat, produced the 

 larva which attained development by means of nutriment. The larva 

 fed. voraciously, and after undei'going many changes of skin, attained 

 its full size, and then changed into the pupa state, during which it lived 

 upon its own fat Burmeister says that, " during the pupa state the 

 intestinal canal of the larva shrivels up, and at its expense the organs 

 of generation are developed." When the last transformation had 

 been completed, the perfect insect made its appearance in the highest 

 state of its development. The end of this last stage of its being 

 appeared to be propagation and the commencement of the cycle of a 

 new generation . 



Whilst on this part of the subject, he would read an extract from 

 a paper communicated to the Journal of the Philadelphian Academy 

 of Natural Sciences by the late Dr. Brackenridge Clemens. In this 

 paper Dr. Clemens says " Every mature or perfected being has had an 

 anterior organic history included in the history of its structural pro- 



