Bla 24 



Blastula. — The stage of development of the egg ; 

 a hollow bag with a cellular envelope formed by 

 the nuclei moving towards the margin of the 

 egg, where they arrange themselves in a layer 

 surromiding the yoke, their masses of protoplasm 

 become marked off into distinct cells and a cell- 

 layer, and the blastoderm is thus formed internal 

 to the yoke membrane. (Gr. hlastos, a germ.) 



Blind ocellus. — An eye of colour without any pupil. 

 (A.S. blind, -j- Du. blind, to become dim, and 

 ocellits.) 



Blood-gills. — Delicate anal tubular processes into 

 which the blood flows, and which do not as a rule 

 contain trachese, though occasionally very fine 

 tracheal branches are to be seen in Irichopterous 

 larvae. (Muller.) (A.S. hlod, + Du. bloed ; 

 and M.E. gille.) 



Boreal. — Of, or belonging to the north. (i^tcp.) 

 {From Gr. and L. boreas, the north wind.) 



Botryoidal. — Cilustered like a bunch of grapes. 

 (Gr. botrys, a bunch of grapes, and eidos, like.) 



Bound. — (Pupfe). (F. borne, to restrain, limit.) 

 See Pupne contignte. 



Bouton.^The ladle-like organ situated at the 

 apex of the lingua in the higher Apida". (F. 

 button.) 



Brachelytrous. — Possessing short elytra. (Gr. 

 brachys, short, and elytron, a wing case.) 



Brachial nervures. — The nerves of the anterior or 

 front wing, which originate at the thorax and 

 run parallel with the interior edge, towards the 



