CLASSIFICATION. 37 



to one of the most important parts of their internal 

 anatomy. 



The structure of the mouth, as far as it goes, is 

 unfavorable to the view of those who regard the 

 CoLLEMBOLA as truo insects. I quite agree with Dr. 

 Meinert that the mouth differs essentially from both 

 the principal types found among insects, without, how- 

 ever, making any near approach to that of the Myria- 

 poda or the Arachnida.^ 



The presence of a saltatory caudal appendage must 

 be taken into consideration. It is very remarkable 

 that no similar apparatus is possessed by any one of 

 the almost innumerable insects, many of which, how- 

 ever, possess the power of leaping in a high degree. 

 Nor, on the other hand, do any of the Collembola jump 

 like Gryllus, Haltica, or Pidex, by means of their hind 

 legs. The true value of such a character as this, how- 

 ever, is as difficult to estimate as it is easy to apply. 



The same observations apply to the ventral tube, 

 which, as I have already observed, is even more charac- 

 teristic of the Collembola than the caudal appendage. 



As the upshot of all this, then, while the Collembola 

 are clearly more nearly allied to the Insecta than to 

 the Crustacea or Arachnida, we cannot, I think, regard 

 them as Orthoptera or Neuroptera, or even, in the 

 strictest sense, as true insects. That is to say, the 

 Coleoptera, Orthoptera, JSTeuroptera, Lepidoptera, &c., 

 are, in my opinion, more nearly allied to one another 

 than they are to the Poduridce or Smynthuridce. On the 

 other hand, we certainly cannot regard the Collembola 

 as a group equivalent in value to the Insecta. If, then, 

 we attempt to map out the Articulata, we must, I 



1 I say any "near" approacli, because, as Mr. Humbert lias pointed 

 ont to me, tlie moutli-parts oi Scolopendrella in some points approach those 

 of the Collembola. This genus, indeed, apj)ears to be more interesting 

 and peculiar than either Gervais or Newport supposed. For instance, 

 it has on the underside of each segment a pair of appendages closely 

 resembling those of the Lepismidce — a fact which suggests doubts 

 whether the subabdominal appendages of that group really represent the 

 legs of Myriapoda. 



