Tns. 1 
INSECTA. 
THE GENERAL SUBJECT. 
By E. C. Rye, F.Z.S., M.E.S. 
Bellesme, J. de. [See PiiiEZ, infrd.~\ 
Bertkau, P. Bericht iiber die wissenschaftlichen Leistuugen im 
Gebiete der Arthropoden wahrend der Jahre 1877-78. Arch. f. Nat. 
xliv. 2, pp. 662. 
Pp. 364-401 refer to Insecta generally, the remainder being devoted to 
Coleoptera (the only portion published in 1878). 
Binzer, — TON. Insecten-Kalendor. Lebcnsphasen imd Frassperioden 
der wichtigsten schadlichen Fortsinsecten. Berlin : 16mo, 2 pis. 
[Zool. Anz. i. p. 22.] 
Bobretzky, N. [On the question of the development of blastoderm in 
Insects. In Russian; in the “Sapiski,” or Memoirs, of the Kietf 
Naturalists’ Society, v. pp. 18.] 
— ; — . Ueber die Bildung der Blastoderms und der Keimblatter bei den 
Insecten. Z. wiss. Zool. xxxi. pp. 195-216, pi. xiv. 
The author’s researches as to the earliest appearance of embryonal 
development in the eggs of Lepidoptera, based upon experiments on 
Pieris cratcegi Porthesia clirysorrJioea^ result in the opinions: — (1) 
That before the appearance of blastoderm an increase of the formed 
elements in the yelk occurs, consisting of protoplasm with a nucleus, and 
having the morphological value of a true cell ; (2) that one portion of 
these elements gradually leaves the yelk for the egg-surface, producing 
the blastoderm, in which no special germ-layer has any share ; (3) that 
another portion of them remains for the formation of the blastoderm in 
the yelk, and causes the subsequent division of the latter into the so-called 
yelk-flakes or balls, which are to be considered as true cells. As to the 
first two of these conclusions, Bobretzky’s observations accord in the main 
with those of Brandt ; but in the 3rd he differs fundamentally from that 
author, who considers that the elementary substances leaving the yelk 
for the surface are of entirely similar formation to the primary germ- 
vesicles. 
1878. [tol. XV.] 
B 20 
