PREFACE. Vll 



ponding to the stigmata, and two antennte, characterize the 

 class of Insects. Its primary divisions are founded on the 

 three following considerations : 



1 . Apterous Insects which either imdei'go no metamorpho- 

 ses, or but imperfect ones ; the three first orders. 



2. Apterous Insects which experience co?npIete transfor- 

 mations ; the fourth. 



3. Insects having wings which they acquire by metamor- 

 phoses, either complete or incomplete ; the last eight. 



I begin with the .Irachnides antennistes of jM. de Lamarck, 

 which arc comprised in this first division, and which form our 

 three firet orders. The second is composed of the fourth 

 order, and contains but a single genus, that of Pulex : it would 

 appear, in some respects, to be allied to the Diptera by means 

 oi the Ilippoboscx ; other characters however, and the na- 

 ture of its metamorphoses, remove this genus from that of the 

 HippobosciB. It is very difiicult in some cases to distinguish 

 these natural filiations, and when we are fortunate enough to 

 discover them, we are frequently compelled to sacrifice them 

 to the perspicuity and focility of the system. 



To the known order of winged Insects, I have added that 

 of the Siresiptcra of Kirby, but under a new denomination, 

 viz. that of Bhipiptcraj as the former appears to me to be 

 founded on a false idea. Perhaps we should even suppress 

 this order, according to the opinion of Lamarck, and unite it 

 with that of the Diptera. 



For reasons elsewhere developed(l), and which I could 

 easily strengthen by additional proof, I attach more conse- 

 quence to characters drawn from the aerial locomotive organs 

 of Insects, and to the general composition of their body, than 

 to the modifications of the parts of the mouth, at least when 

 their structure is essentially referable to the same type. Thus 

 I do not connnence by dividing these animals into Grinders 

 and Suckers J but into those which have wings and wing-cases, 

 and such as have four or two wing-s of the same consistence. 

 The form and uses of the organs of manducation are viewed 



(1) Consid. GciKT. sviv rorJre dcs Crust., des Arach., et des Insectes, p. 46. 



