ii6 



The Flv of Chironomus 



Male 

 organs. 



by the secretion of the giuten-ghaiid ; this consists of 

 transparent mucilage, and is shaped into a cylinder with 

 rounded ends. The detailed structure of the cylinder is 

 described in chap, vi, p. 153. 



The contents of both ovaries and of the gluten-gland 

 are discharged simul- 

 taneously. "As in many 

 other cases of coated eggs, 

 first 

 but 

 on 

 In 



the mucilage is at 

 scanty and dense, 

 swells enormously 

 reaching the water 

 some species of Chiro- 

 nomus the contents of the 

 two ovaries seem to le- 

 main distinct, except that 

 they become fused at one 

 place. In C. dorsalis they 

 are intricately blended. 



The male organs of the 

 fly consist of a pair of 

 testes, a pair of sperm- 

 ducts, and an ejaculatory 

 duct. The testis, when 

 ripe, is filled with long- 

 simple sperm - filaments, 

 developed as usual from 

 compound cellular masses 

 (spermospores) which arise 

 by repeated division of 

 single cells. The sperm- 

 ducts are long and slender, and pass backwards as 

 far as the junction of the penultimate with the last 

 abdominal segment, where they open into the ejacu- 

 latory duct. This now passes forwards for a consider- 



Fio. 87. — Male genital organs of fly. 

 (, testis, vd, vas deferens, g, d, ejacu- 

 latory duct, vs, vesicula semiualis. 



