No. I.] CONTRIBUTION TO INSECT EMBRYOLOGY. 



33 



connection with the hypodermis. In a little later stage than 

 the one here described the columella and the conical lump of 

 inner indusial elements have disintegrated, and can no longer 

 be distinguished from the granular amniotic serum. 



The changes in the configuration of the embryo since its 

 arrival on the ventral yolk, relate mostly to the appendages. 

 At first the antennae are of about the same thickness as the 



-5XC 



Fig. IV. 



Sagittal section through the anterior pole of a Xiphidiu7n embryo, with pig- 

 mented eyes, ch., chorion ; cL, columella ; s}-. c, Blastodermhaut ; sr., serosa ; 

 uid'^ + a7n., remains of the inner indusium and amnion ; ind'^, outer indusium ; 

 ind^ s., secretion of the inner indusium; am. s., amniotic secretion; /v. c^, first 

 larval cuticle ; h'. c~, second larval cuticle ; dr., brain ; e., eye. 



legs. The dark line running parallel with their inner edges, 

 and distinctly marked in Fig. 9, is in section seen to be a meso- 

 dermal partition dividing the cavity of the appendage into two 

 tubular sinuses. The antennas grow directly tailward till their 

 tips reach the femorotibial joint of the hind legs, when they di- 

 verge laterally, describe an arc, and then grow forward. When 

 the tips have reached the head further progress is arrested 



