378 ON THE ORDERS 



which he always, on its detection, mentions an affinity at 

 the moment even when it directly contradicts the accuracy 

 of his distribution. 



In the Genera Insectorum M. Latreille reckons that the 

 Sucioria of Degeer, as the last order of the Hexapod in- 

 sects, immediately follow the Diptera, and even in the 

 Re^ne Animal he allows this to be their natural place. 

 In good truth, however, this is to be accounted only half the 

 situation which the order ought to possess. Fabricius was 

 more bold and less correct ; for he placed the genus Pulex, 

 not even at the end of the Sy sterna Khyngotorum, but be- 

 tween Zelus and Aphis, with which last it certainly has some 

 remote affinity. But it is to M. Lamarck, who united these 

 opinions of Fabricius and Latreille, that we are indebted 

 for the knowledge of its tme place in the scale of creation, 

 and therefore the very least return we can make is to adopt 

 his name Aptera for the order- I am the more disposed to 

 insist on this point of nomenclature, because it is a classical 

 denomination, which, owing to the later improvements in the 

 science, would otherwise be lost. But it must not be under- 

 stood that every insect which belongs to the group is there- 

 fore of necessity Apterous ; this is perhaps no more true than 

 if, in adopting Degeer'sword, we should therefore conclude 

 that the order contains every insect which lives by suction. 



The Aptera contain undoubtedly the type of a very 

 distinct order; for they are the only animals in the class 

 of Haustellata which have a bivalve articulated sheath to 

 iheir rostrum. " La puce," according to Lamarck, " tient 

 beaucoup aux Dipteres par la metamorphose* , car sa larve 



• Leeuwenhoeck claimed and has acquired all the honour of this dis- 

 covery ; but in fact it was half known in the days of Aristotle, who observed 

 not only that the Pulicesh^A distinctsexes, but that they produced exuXnxts 

 mtihus. From not following the metamorphosis further, he fancied this 



