CLASSIFICATION OF INSECTS. 331 



affinities of the various groups are more or less clearly 

 pointed out and adopted. It would occupy too much time 

 to trace the gradual improvements, or suggestions for im- 

 provements, which have been made during the present 

 century, in which Entomology has made such rapid strides 

 towards perfection. 



The breaking up of the heterogeneous mass of the Linmcan 

 apterous insects, by the establishment of the classes Crustacea, 

 Arachnida, and Ametabola, together with the proposal of the 

 order Orthoptera, by Olivier, for the masticatory Hemiptera 

 (grasshoppers, &c.), Strepsiptera, Trichoptera, and Aphani- 

 ptera, by Mr. Kirby, the separation of the Cicada, &c., 

 from the other Hemiptera, under the name Homoptera, by 

 Latreille, together with the proposal of several other orders 

 of minor importance, subsequently noticed, must not be for- 

 gotten. Neither ought the system of MacLeay here to pass 

 unnoticed, established with the view of obviating the diffi- 

 culties which constantly attend our endeavours to arrange 

 our species in a continuous linear series of affinity, and 

 which evidently prevents our harmoniously combining their 

 varied relations. 



The following diagram will be sufficient to explain, as far 

 as the true insects are concerned, the manner in which this 

 is proposed to be effected by Mr. MacLeay. 



