424 Recent Literature. [ July, 
authors. “My own observations,” says he, “embrace several Diptera 
(Anthomyia, Sarcophaga, Musca domestica, Seatophaga, Eristalis, Stra- 
tiomyia) ; several species of Formica and Myrmica; one Lepidopteron, 
Lithocolletis ; and of Coleoptera, Tenebrio and Chrysomela. Amon 
the Diptera, my fullest researches were those on Anthomyia rufipes: 
a smaller species being ‘easier to handle in preparing cross-sections, 
especially in the pupa state, when most of the organs are destroyed. 
In Sarcophaga carnaria, I observed the structure and the development 
of imaginal discs, anterior to pupation. The relationship of this species, 
as well as of Musca vomitoria, studied by Weismann, to Anthomyia 
authorizes the assumption that whatever is explained here about the de- 
velopment of the latter genus is equally applicable to Musca vomitoria 
and Sarcophaga carnaria, and also to the other above-named Muscide.” 
“More or less complete are my observations on the development of 
the teguments of the head, the thorax, and the abdomen, with their ex- 
crescences ; also on the development of the alimentary canal. The aim 
of my studies was not so much to investigate the details of the develop- 
ment of this or that organ as to observe the mode of formation of the 
rudiments of organs, the material out of which they are developed, and 
the time of their appearance. Many facts, introduced into science by 
Weismann, — for instance, those which refer to the part played by the im- 
aginal discs in the development of the imago, — must retain their scien- 
tific weight, with slight emendations, with respect to the development and 
structure of those discs; but another category of results, elicited by 
Weismann, — namely, those relating to the histolytic processes, the for- 
mation of the tissues of the imago from the produce of the destruction of 
the organs of the larva, — must be considered as erroneous and replaced 
by others.” (Pages 4, 5.) : 
The main portion of the. author’s dissertation is divided into = 
chapters, which embody his own observations, and are entitled, Imaginal 
dises (Muscide); History of the development of the head ; History of the 
development of the abdomen of the imago; Adipose body and destructive 
processes; Imaginal dises of the ant (Myrmica); History of the develop- 
ment of the leg of Lepidoptera and Coleoptera ; History of the develop- 
ment of the alimentary canal (Muscidze); History of the development of 
the proboscis; History of the development of the alimentary canal of 
Myrmica, Lithocolletis, and Tenebrio. 
It would be impossible fairly to render the contents of these chapters 
without translating the whole of them; it will suffice here to give be 
translation of the concluding chapter (page 64), which sums up the author? 
results and views. “ Conclusions. In consequence of the above-statec 
facts, as well as of several still unfinished researches of mine organ 
_ ing the development of the central nervous system and of the vat 
vessel, we may reach the conclusion that the formation of the o 
of the imago, during the period of its post-embryonal deve 
lopment, 18 
