ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 783 



orders of insects, and from them concludes, that (1) carnivorous 

 insects are not inferior in beauty to those which feed on flowers, &c. ; 

 and (2) that the flower and fruit eating group contains amongst them 

 numerous dull-coloured species. 



Development of the Bee.* — In studying the eggs, Prof. B. Grassi 

 traced the external features by examination in the fresh state ; for 

 sections, the eggs were hardened either in hot water at a temperature 

 of 70° C. or in picric acid ; they were then treated with alcohol and 

 stained with picrocarmine. The egg is an ovoid cylinder, rounded at 

 each end ; at the larger (anterior) end is placed the micropyle ; one 

 face, the future ventral surface, is convex ; the other concave. The 

 chorion, which closely surrounds the egg, in spite of its thinness, is 

 very tough, and prevents the action of reagents upon the protoplasm ; 

 and as it cannot be removed without injuring the egg, it was found 

 best to pierce it in various places in different eggs. The embryo, 

 when formed, is not coiled within the egg-shell, but is of the same 

 length as the egg. 



The vitelline* membrane described by Biitschli was not found. 

 At the end of each paragraph the author refers to and discusses tho 

 results of previous authors. 



I. S2>ecial part : (a) formation of blastoderm. — No polar bodies 

 nor amoeboid nuclei were observed ; the egg consists of vitellus, in 

 which no nucleus is visible ; soon a space appears at each end of the 

 egg ; and at the anterior pole, two cells are seen. These are followed 

 by four cells and so on — all remaining united, and giving rise to a 

 blastoderm, which extends all round the vitellus ; the cells forming 

 it being smaller on the future ventral than on the dorsal surface. 

 The cells on this latter surface are large and multinucleate, and 

 separate from one another, but they soon disappear, apparently by 

 shrinking of the blastoderm, so as to leave the vitellus, which consists 

 of oily globules, uncovered over a certain area. 



b. Amnion. — The cells of the ventral surface of the blastoderm are 

 small, whilst those at the sides are larger ; the former set gives rise 

 to the ventral plate ; the latter becomes the amnion. There first 

 forms a space at each end of the vitellus ; the walls of the spaces are 

 partly formed by the amnion, partly by the ventral plate. 



During the formation of the germinal layer the edges of the amnion 

 meet over the embryo and coalesce, so as to form a covering containing 

 liquid ; this amnion is only one cell thick, and is probably derived 

 from the cells from the dorsal surface of the blastoderm ; no new cells 

 emigrate from the yolk to form it. 



c. The germinal layers — Along the greater extent of the ventral 

 plate there appear two longitudinal, undulating grooves, one on each 

 side of the median line. The middle portion between them becomes 

 nipped off, so as to form meso-entoderm, whilst the lateral portions 

 then grow over the depressed area and unite, leaving no trace of their 

 union ; this forms the ectoderm. 



The process commences anteriorly and gradually extends back- 



* Arch. Ital. Biol., vii. (1886) pp. 242-73. 



