Anopheles theobaldi. 



genus Nyssorhynchus apparently depends upon the presence or 

 absence of these few scales. 



The wings are covered with spindle-shaped scales. The costa 

 has six black-scaled areas. The black-scaled portion on the centre 

 of the costa is the largest. Two very small dark spots are situated 

 at the inner end of the wing. 



The first longitudinal vein has four dark markings correspond- 

 ing with the four outer large dark areas on the costa. The third 

 dark area from the outer end is almost always divided into three by 

 the interposition of two small white-scaled spots. 



The second longitudinal is for the most part white, but shows 

 two black- scaled areas on the main trunk and two dark spots on 

 each of its branches. 



The third longitudinal vein is white except for three dark 

 spots. 



The fourth long vein has two long black spots on the main 

 trunk and two small black spots on each of its branches. 



The fifth longitudinal has only one dark spot on the main 

 trunk, three on its anterior branch, and one on its posterior branch. 



The sixth long vein has three dark spots. 



The distal extremity of all the veins is light-scaled, and at 

 these points the wing fringe is interrupted by light scales. 



The legs are much adorned with white scales and differ in 

 detail in the anterior, mid and hind legs. The femora and tibiae of 

 all the legs are covered with dark and light-scaled spots. The first 

 tarsal segments too have some white spots. The distal extremities 

 of the second and third tarsal segments in the fore and hind legs 

 are white, but black at these points in the middle legs. The fourth 

 and fifth segments in the hind legs are entirely white, while they are 

 entirely black in the other legs. 



Characters of the larva. The frontal hairs are slightly branch- 

 ed or frayed, There are palmate hairs on the abdominal segments 

 and a rudimentary pair on the thorax. The shape of each leaflet 

 is characteristic, and the terminal filaments are very short and 

 blunt. 



The larva of this species differs from most of the others in 

 this group in that it is more frequently found in streams than in 

 still water. 



98] 



