NO. 8 ANATOMICAL LIFE OF THE MOSQUITO SNODGRASS 



27 



them bear on the back pairs of small palmate brushes (e) that suspend 

 the larva from the surface of the water in its usual horizontal feeding 

 position. The respiratory apparatus on the dorsum of the ninth seg- 

 mental region contains a pair of large open spiracles, which are either 



Fig. 10. — Larval respiratory organs. 



A, Anopheles macnlipennis, tracheal system, dorsal (from Imms, 1907). B, 

 Anopheles quadrimaculatus, end of abdomen, spiracular apparatus open. C, Same, 

 spiracular apparatus closed. D, Same, details of spiracular apparatus. E, Culex 

 pipiens, end of abdomen. F, Aedes aegypti, same. G, Culex quinquefasciatus, 

 larva in feeding position. H, Culex pipiens, end of respiratory siphon. 



al, anal lobes; dTra, dorsal tracheal trunk; Sp, spiracle; VIII-X, abdominal 

 segments. 



flush with the surface (fig. 10 A, Sp) or carried out on the end of a 

 respiratory tube (E,F,G). The tenth segment contains the func- 

 tional anus at its end, and bears four lanceolate, thin-walled apical 

 appendages, or anal lobes (A,B,E, al). Flat dorsal and ventral brushes 



