^38 



2. The filament is long and filamentous. ' 



M. rossti ^ " -,-"' ' ^".■.. ■ 



M. culicifacies - ; - . • 



M. listoni 



' N. fuliginosus 



Further differences are seen in the case of most 

 of the above species. In M. rossii the filament is 

 as long as the leaflet, and there is scarcely any 

 notching where the two join. In N. theobaldi, 

 the notching is well marked (Fig. 57B). 



3. The filament is very short, a mere spike- 

 like process. . 1 



N. stephensi 



N. maculata 

 ''. ) N. fheohaldi 



] ' N. maculipalpis 



The Stigmatic Syphon. — The eighth segment 

 bears the stigmatic opening. This is a large 

 quadrilateral space, with hard comb-like chitinous 

 processes on either side. These have the teeth 

 projecting backwards, and are capable of being 

 approximated so as to obliterate the cavity. Into 

 the anterior portion of the space, under cover of a 

 lip-like, process, the two main air tubes open. 



The ninth segment is cylindrical in shape, and 

 is chiefly notable from the fact that it carries four 

 large transparent papillae well supplied with air 

 tubes and certain long curved hairs. Of the hairs 

 one series projects downwards so as to resemble a 

 rudder. The others project posteriorly." There 

 does not appear to be much variation in the 

 different species. 



