some Dipterous Larvce. 



605 



three main portions : — (1) the basal or pharyngeal sclerite 

 (p), the lateral parts of which are strongly chitinised, while 

 the ventral part, which forms the floor of the pharynx, is 

 thin, transparent, and thrown into longitudinal ridges which 

 project into the pharyngeal lumen ; (2) the intermediate 

 sclerite (i), in the form of an H, its anterior space being 

 occupied by a hypophary ngeal sclerite (h) ; (3) the lateral 

 hooks (/), which are well developed and each provided with 

 a single tooth only. 



Description of Larva B,from the Branchial Chamber 

 of Gecarcoidea lalandii. 



The single specimen of this larva which I have been able 

 to examine is in the second stage. It measures 2'3 mm. by 



Larva B: Fig. 5. — The larva seen laterally. Fig. 6. — Protlioracic 

 spiracle during the moulting. Fig. 7. — Postabdominal spiracles. 

 Fig. 8. — Bucco-pharvngeal armature. The scale represents only the 

 magnification of fig. 5. 



0"25 mm. Its body also is comprised of a small pseiulo- 

 cephalon, three thoracic, and eight abdominal segments 

 (fig. 5). The anterior and posterior margins of each seg- 

 ment bear several sinuous rows of small booklets. The last 



