1 8 Mosquitoes 



and branched, or with many tracheoles. The gills may 

 be blunt or pointed ; sometimes they are spotted. 

 As this maculation is a structural character, which 

 can be brought out by alcohol or formalin in dead 

 specimens not showing spots when alive, the patches 

 being apparently formed of large granular cells, it is 

 not a trustworthy character for classification unless 

 the specimens are identified alive. Sometimes the 

 gills have two or more constrictions. The lower 

 pair of gills often differs greatly from the upper in 

 size, especially so in the case of the pitcher-plant 

 larva. On the ninth segment, below the gills, is 

 usually a series of long tufts on stems arising from 

 a barred area. This series is sometimes wanting, in 

 which case there are more hairs around the termina- 

 tion of the segment. Above the gills are a pair of 

 long tufts and a pair of long, usually single, hairs or 

 bristles. 



Pupae. — The pupa is the form intermediate be- 

 tween the larva and the adult. Unlike most pupae, 

 those of the mosquito are very active, but, like other 

 pupae, they do not eat. They are about the shape of 

 fat commas (Fig. 4, page 19), floating quietly at the 

 surface or bobbing crazily downward at the least 

 alarm, to hide at the bottom, propelled by backward 

 flips of the abdomen. On close inspection the head 

 and thorax will be seen to be all together. Through 

 the chitin the head of the adult may be distinguished, 

 with its mouth-parts and eyes, the legs neatly doubled 

 up under the head, the wings folded in their cases 

 — even the veinings distinguishable beneath the 

 delicate coverings. The creature no longer breathes 



