153 
CHAPTER XXII. 
METAMORPHOSIS. 
Developrnei'it of E7nbryo — Micropyle — Choi'ion — Vitelius and 
Blastodenji — Ajitnion — Ectodei'm and Mesoderm — Nei'vous 
System — Ganglia — Trachece and Spiracles — Alhnentary 
Tract — Dorsal Vessel — Appendages — Apodal Larva — Moult - 
ing — Spinning Cocoon — Transformations — Ga/iglia in 
Various Stages of Developfnent — Blind I^itestine i?i Lamja — • 
Wi?zgs — Silk Glands — Appearance of Egg Germs — Period of 
Rest. 
Before we proceed to describe the various changes 
the bee goes through from the time it leaves the egg 
as a tiny grub to the time it emerges from the cell as a 
perfect insect, which are called itielatnorphosis^ it will be 
well for us to briefly explain the various stages of de- 
velopment of the embryo within the egg itself from the 
moment of its fertilisation. The subject has been 
investigated by Tichomiroff (162), Kowalewski (80), 
Biitschli (18) ; and in 1883 and 1884 Dr. Grassi (56) 
published his excellent and elaborate memoirs, in which 
he goes very minutely into the subject. The labour of 
this work may be estimated Avhen we state that each 
egg was cut into no less than eighty sections to arrive 
at a proper construction. As the fresh egg is very 
transparent, he was able in every case to compare it 
with the sections taken from eggs of the same age. 
The egg as laid, is an ovoid cylinder (Fig. 57, a), 
rounded at each end ; the upper one, n (which at a later 
period contains the head of the larva) is the larger of the 
