PLAXT-HOUSE ALEVRODES. 97 



son."^ The house was then closed and left, in various experi- 

 ments, from forty-five minutes to fourteen hours. When the 

 fumigation was given early in the afternoon of a bright dav, the 

 tomato plants were injured by the use of one ounce cynanide to 

 1000 cu. ft. of space. The same amount caused no trouble, how- 

 ever, when the fumigation was postponed until evening, a fact 

 which verifies Johnson's statementf. \Mth i oz. cyanide to 1500 

 cu. ft. of space the plants were not injured. In no case, how- 

 ever, is it considered advisable to fumigate when the sun is shin- 

 ing brightly, or when the temperature is above sixty degrees. 



*. Johnson, fumigation methods, pag'es 9 and 118. 

 flbid. 145. 



EXPLAXATIOX OF FIGURES. 



Fig. 41. Egg. X130. 



Fig. 42. Newly hatched larva from the ventral side. X130. 



Fig. 43. Pupa from the dorsal side. X130. 



Fig. 44. Longitudinal section of a mature egg in the ovary of the 

 female. X530. 



Fig. 45. Longitudinal section of an egg when the invagination of the 

 germ band has begun. X530. 



Fig. 46. Adult female from the left side. X130. 



Fig. 47. Side view of egg with embryo, just before closure of amni- 

 onic cavity. 



Fig. 48. Reconstruction of a fully developed embryo just before 

 hatching. 



Fig. 49. Ventral view of the germ band after segmentation has begun. 

 X530. 



Fig. 50. Male reproductive organs seen from above. X130. 



Fig. 51. Reconstruction of an adult female shown with the dorsal 

 part of the body wall removed. X130. 



