706 



APPENDIX. 



not assuming their strange forms. From the non-segmented, 

 sac-like larva it passes directly into the pupa state. 



The development of Teleas is like that of Platygaster. 

 Fig. 656 A, represents the egg ; B, C, and Z>, the first stage 

 Fig. 656. of the larva, the ab- 



domen (or posterior 

 division of the body) 

 being furnished with 

 a series of bristles 

 on each side. B 

 represents the ven- 

 tral, C the dorsal, 

 and D the profile 

 view ; at, antennae ; 

 md, hook-like man- 

 dibles ; mo, mouth ; 

 6, bristles ; m, intes- 

 tine ; sw, the tail, 

 and ul, under lip, or 

 labium. In the sec- 

 ond larval stage, 



Development of Egg-parasites. "~ 



which is oval in form, and non-segmented, the primitive band 

 is formed. 



THE EMBRYONAL MEMBRANES OF INSECTS. After the forma- 

 tion of the germinal layer or blastoderm, the outer layer of 

 blastodermic cells peels off or moults, forming the so-called "am- 

 nion" ("parietal membrane" of Brandt, Fig. 657, am). This 

 skin is a moult from the blastoderm. At a later period, after 

 the formation of the primitive band, a second membrane (Fig. 

 657, db "faltenblatt" of Weismann ; visceral layer of Brandt) 

 separates from the primitive band. It surrounds the embryo 

 in the Hymenoptera, Diptera and Coleoptera, enveloping the 

 limbs, and is shed as a thin pellicle when the embryo leaves 

 the egg. Melnikow (Archiv fur Naturgeschichte, 1869, p. 136) 

 from whose article the accompanying figure is taken, shows 

 that in the lice, however, both the amnion and visceral mem- 

 brane share in building up the body of the embryo, and pass 

 upon the dorsal side of the embryo. Brandt (Memoirs of the 



