DAHLGREN, THE MALARIA MOSQUITO 19 



darts downward instantly when disturbed. If confined in a glass vessel, 

 it may be seen on such occasions to strike the bottom repeatedly, return- 

 ing to the surface of the water by its own buoyancy as soon as its 

 movements cease. The downward swimming is accomplished by a few 

 vigorous strokes of the strongly curved abdomen, which bears at its tip 

 a pair of "paddles," or "flippers," and is the only freely movable part of 

 the bodv. 



FIG. 13. THE PUPA OF THE MALARIA MOSQUITO. FEMALE. 



Photograph of the model (X 75) in the American Museum. Magnification of 

 the figure about 15 diameters. 



Under the transparent integument of the pupa may be seen outlined 

 the bodv and appendages of the developing mosquito (Fig. 

 15). The head is drawn up against the anterior part of the f Pupa 

 thorax, giving the puj a its characteristic hunchbacked ap- 

 pearance. The strongly flexed abdomen curves downward and forward 

 under the thorax. The elongated mouth-parts, the "proboscis" of the 



