No. 480] 



BLOOD GILLS OF SLMULIUM 



877 



hot Gilson's fluid were about equally successful. The material 

 killed in the former cut easily but showed some shrinkage, while 

 that prepared with the latter cut less easily and showed less shrink- 

 age. The Flemming material cut so poorly that the preparations 

 made from it were of little value. By staining on the slide with 

 Gage's hsematoxylin and orange (t, the tissues were well differ- 

 •entiated. 



In the living larva the gills are white, soft, and translucent, and 



appear on tl)e dorsal side of the last abdominal segment, just ante- 

 rior to a dark, strongly chitinized, X-shaped piece (Fig- L A. a, h). 

 They are projections of the ventral wall of the rectum and lie, 

 when retracted, completely within the rectal cavity (Fig. 2, A). 



