158 STATES OF INSECTS. 



gard to the larvae of Lepidoptera and the saw-flies ( Ten- 

 thredo L.) have been made both by Reaumur and De 

 Geer. M. Latreille also has recently given a Tableau 

 methodique et general of articulated animals furnished 

 with jointed legs, considered in their first state a . The 

 former of these is chiefly founded upon the number of 

 the prolegs, and the latter upon the metamorphosis, pro- 

 legs, habits, head, and parts of the mouth, without any 

 other notice of the configuration. Mr. Wm. MacLeay, 

 who, though young in years, is old in science and critical 

 acumen, has started a perfectly new hypothesis upon this 

 subject. In the progress of his inquiries into the natural 

 arrangement of animals, particularly of insects in the 

 Linnean sense, he has been the first to observe, that the 

 relation which organized objects bear to each other is of 

 two kinds ; one of real affinity, and the other only of ana- 

 logy, or resemblance. This important distinction, upon 

 which I shall enlarge in a future Letter, when I come to 

 treat of Systems of Entomology, he has applied, in a way 

 quite original, to larvae in general, but more particularly 

 to those of the Coleoptera order. For the basis of his 

 system he assumes a relation of analogy between the 

 larva of Insects that in the progress of their metamor- 

 phosis assume wings, and those that do not, which form 

 his class Ametabola, so that the prototypes of the former 

 shall be found amongst the latter 5 . But though Mr. 

 MacLeay appears to consider the analogy between these 

 two as primary, he extends it in a secondary sense to the 

 Crustacea, at least in several instances c . Upon this oc- 



a 2T. Diet. d'Hist. Nat. xvii. 329. 



b Hor. Entoviolog. 285. 397—. 422. 462—. &c. 



c Ibid, 399—401. 



