398 ON THE ORDERS 



analogy to the Chilopoda; the form of an lulus is easily 

 discoverable in the cylindrical cruciform larvae of the 

 Trichoptera, while the apod larvas of the Hymenoptera 

 are described by the first zoologists as resembling an 

 intestinal worm in form as well as manners*. I shall 

 ieave the analogy between the Coleoptera and Ametabola 

 to be discussed in a future chapter; only stating, for the 

 present, that so far from the other analogies being fanci- 

 ful, it can be proved by citations from the works of the 

 best entomologists that they have been severally noted by 

 them, although without any view to arrangement, or in- 

 deed any object beyond the mere mention of the fact. 

 Compare Lamarck's descriptions of the genera Blatta and 

 Lepisma, and it will be seen in how few circumstances 

 some Thysanura differ from the larva? of the first mentioned 

 genus. I mean few circumstances according to the descrip- 

 tion, for there is enough of dissimilarity evident to show that 

 the relation between them is only one of analogy. Let any 

 one read Latreille's description of the larva of an Hemero- 

 bius or Raphidia, and, except that it is hexapod, he may 

 easily believe that a Scolopendra is meant. IN ay, the greatest 

 part of the aquatic larvas of Neuroptera have false feet or 

 branchiae, which complete their Scolopendriform appear- 

 ance. The similarity between an lulus and the larva of a 

 Tenthredo is carried even to such a pitch, that the number 



* M. de Humboldt's Anatomical Account of the worm Porocephalus Cro- 

 tali, which he discovered adhering to the oesophagus and pulmonary sac 

 of a South American Rattlesnake, affords us an interesting example of the 

 relation of analogy between intestinal worms and the larvas of the internal 

 orders of insects. Nothing is more remarkable in the metamorphosis of 

 these last, than theirpropensity, when larvas, to secrete fat for the absorption 

 and nutrition of the insect during the period when it is unable to eat. Now, 

 M. de Humboldt says of the abovementioned intestinal worm, " Tout le corps 

 de V animal a ^exception de deux extremites est rempli de Jils vermiformes 

 d'un Mane laiteux, qui paraissenl avoir de I' analogic avec les lamheaux grais^ 

 senx (epiploons) qui flottent dans Vinterieur des larves des insectes, et surlout 

 avet les ovaires pelelonncs des dsiarides.'" 



