225 



Within each type great variation usually 

 exists in the different species. The following are 

 the most notable variations found : — 



1. 7'he Frill. — The width. The continuity 

 of the frill around the whole of the margin of 

 the upper surface or its replacement in the middle 

 third by the floats. The extent of striation of the 

 frill. The presence of a striated rim only. 



2. The Floats. — The position, placed forwards 

 and encroaching on the upper surface, or laterally 

 situated. The shape, oval, globular, or scallop- 

 shell. 



3. The Lower Surface. — Whether ornamented 

 or not with silvery reticulated pattern. 



The following is a brief resum6 of the 

 characters of the ova of Anopheles, as far as these 

 have been described : — 



Type' I. M. sinensis, suh-sp. nigerrimus 



Ovum. — Upper surface very narrow. Floats 

 do not touch margin of upper surface. Lower 

 surface of ovum ornamented with polygonal 

 markings. 



M. barbirostris 



Ovum. — Upper surface very narrow. Floats 

 do not touch margin of upper surface. Lower 

 surface of ovum ornamented with polygonal 

 markings. 



M. culicifacies 



Ovum. — Upper surface very narrow. Floats 

 do not touch margin of upper surface. Lower 

 surface not ornamented. A short but distinct 

 fringe is continued around margin of upper 

 surface:' 

 Q 



