A. S. Packard, Jr. on certain Entomological Speculations. 211 



and pupa of insects generally, we do not feel prepared to accept. The 

 works of Herold,* Siebohl.-j- Claparede,J and Weismann,§ show in a 

 most convincing manner, that the apodal, acephalous form, is com- 

 mon in the embryonic ur ante-larval life of those insects whose me- 

 tamorphosis is most complete. 



The terms larva and pupa are useful as conventional terms among 

 naturalists, but they are by no means fixed, immutable shapes in the 

 majority of insects. Though these stages are less transient in the 

 Lepidoptera and Diptera and Coleoptera, from special ends in their 

 economy ; Mr. Lubbock has shown that the Ephemera (Chloeon ) 

 , moults twenty times, which involves a succession of twenty-one dis- 

 tinct forms before the insect reaches maturity. 



In the development of the Humble Bee (Bombus), we have shown 

 that it is difficult to draw a definite line, in life, between the embryo 

 just before leaving the egg. and the recently hatched larva; between 

 the larva and semi-pupa, and between the so-called pupa and adult 

 bee, so gradual are the changes which lead from one stage to the other. 



By no means, then, can we subscribe to the astounding state- 

 ment made in another place, || that " Authors are perpetually forget- 

 ting that Annulate animals pass from one state to another only by 

 suddenly moulting their skeletons, while vertebrate animals retain 

 the same skeleton throughout, and pass from one state to another by 

 the slow and gradual accretion of new matter," p. 563. 



Are we to be again troubled by comparisons between the crust 

 (arthruderm) of articulates, and the skeletons of vertebrate animals'/ 

 Why dig up from their graves these long-buried notions of Gr. St. 

 Hilaire and other writers of that school, who suggested such views, 

 brilliant as at first sight they seemed, though now confessedly obsolete? 



Again, hear our objector — "I am also very skeptical as to certain 

 assertions of Harris and Fitch, that the larva of Cecidomyia trans- 

 forms gradually into the pupa state, by a kind of budding process, 

 without moulting the larval integument, instead of suddenly moulting 

 into the pupa state, as in all other insects. This theory seems to have 

 been devised in order to harmonize with the erroneous hypothesis 

 already referred to. viz : that the cocoon of the Hessian Fly is made 

 out of the external integument of the larva, and so prevent the 



Exercitationes de animalium vertebfis carentiura in ovo formatione. 1824. 

 f Observations de primo insectorum genesi. 1842. 

 + De devolution des Araignees. 1865. 

 , Die Entwicklung der Dipteren. 1864. 

 On the Insects, Coleopterous, Eymenopterous and Dipterous, inhabiting 

 the galls of certain species of willow. Tart 1st. — Diptera. By B. D. AVulsh, M. 

 A. Proe. Eut. Soc. Phil., Dec. 1864, p. 543. 



