380 ON THE ORDERS 



of the transition which here takes place, than any other ar-* 

 gument in my power to advance. Nay, if a person should 

 object to the foregoing detail of affinities, it would in my 

 opinion be perfectly allowable to refer him to the attendant 

 analogies, as amounting to a demonstration of its general 

 accuracy. 



There are certain Dipterous insects, however, which 

 before we quit the Haustellata deserve a few moments of 

 particular attention. It is easily seen that allusion is now 

 made to the Pupipara of Latreille, or Mouches-araignees 

 of Reaumur and other French naturalists. The struc- 

 ture of their mouth and organs of locomotion, the nature 

 of their metamorphosis, the texture of their body, but par- 

 ticularly the gradual manner in which the head becomes 

 united to the thorax, and at length almost forms one piece 

 with it, all distinguish these animals from the ordinary 

 type of Diptera, and have lately occasioned their being 

 formed into the osculant order oiliomaloptera. Analogy 

 seems to indicate that they ought to occupy that situation 

 among the Haustellata which, to all appearance, the 

 Strepsiptera occupy in the circle of Insects provided with 

 mandibles. The safest way therefore, in the present state 

 of our knowledge, will be to account it an auxiliary or 

 osculant order like the other. The singular genus Nycte- 

 ribia, or Pthiridiori of Hermann, well known as infesting 

 bats, closes the series of Pupiparous insects, and must 

 satisfy every person that we are arrived among the 



Arachnida, 



of which Leon Dufour has just said that the history 

 is scarcely yet sketched, while our knowledge even of 

 their species is extremely imperfect, notwithstanding the 



