TRACE EAT A. 



347 



which has already been described, and of an abdomen formed of five seg- 

 ments, the last of which bears the somewhat varying caudal appendages. 

 The nervous system is as yet undeveloped. 



The larvae move about in the tissues of their hosts by means of their 

 claws. 



The first larval condition is succeeded by a second with very different 

 characters, and the passage from the first to the second is accompanied by 

 an ecdysis. 



The ecdysis commences at the caudal extremity, and the whole of the 

 last segment is completely thrown off. As the ecdysis extends forwards 



E 



ao 



FlG. 191. A SERIES OF STAGES IN THE DEVELOPMENT OF PLATYGASTER. 



(From Lubbock; after Gauin.) 



A. B. C. Cyclops larvae of three species of Platygaster. 

 D. Second larval stage. E. Third larval stage. 



mo. month ; a. antenna ; kf. hooked feet ; Ifg. lateral feet ; /. branches of tail ; 

 ul. lower lip; slkf. oesophagus; gsae. supra-cesophageal ganglion; bsm. ventral epi- 

 blastic plate ; Im. lateral muscles (the letters also point in D to the salivary glands) ; 

 gh. proctodseum; ga. generative organs; md. mandibles; afj. ducts of salivary glands; 

 sp. (in E) salivary glands; mis. stomach; ed. intestine; ew. rectum; ao. anus; 

 tr. trachea? ; fk. fat body. 



the tail loses its segmentation and becomes strongly compressed, the 

 appendages of the cephalothorax are thrown off, and the whole embryo 

 assumes an oval form without any sharp distinction into different regions 

 and without the slightest indication of segmentation (fig. 191 D). Of the 

 internal changes which take place during the shedding of the cuticle, the 



