244 BANKS. 



The respiratory siphon is slightly less than twice as long as the diameter of 

 its base. It is naked except for the pecten scales, a quadrifid bristle before 

 mentioned, and six minute setae at the apical extremity around the tracheal open- 

 ing. The surface is finely, transversely reticulate or striate. 



HABITS OF THE LARV/E. 



The larvae may be fonnd in all kinds of receptacles where water collects 

 in and around houses. They much prefer rain water and might almost 

 be called an exclusively rainy-season species, being very much more abun- 

 dant at that time than during the months from December to May. 



The full-grown larvge feed almost exclusively at the bottom, coming 

 to the surface occasionally to breathe and always to molt. In the latter 

 ease, unless disturbed, they remain motionless for several hours previous 

 to shedding their skins. 



Wlienever an object comes near, or the vessel is jarred, all larvse go 

 to the bottom where they may remain for several minutes. This feature 

 has a great bearing upon their propagation. As the water in most 

 vessels where they breed is dipped from above, instead of being drawn 

 oflE from a tap at the bottom, the mosquito larvs are seldom dipped up 

 because they dive quickly when the surface is disturbed. Even in a 

 pitcher in daily iise and in which the water is renewed when low, they 

 may successfully complete their life period. Several eases of this kind 

 have come to my notice, the persons interested asserting that the water 

 in the pitcher or other vessel had been renewed daily, but never taking 

 notice of the fact that the small quantity which always was allowed to 

 remain in the pitcher contained the larvse. 



These larvas have never been observed feeding upon one another nor 

 upon the larvas of Culex fatigans Wied., with which they are often 

 associated. They feed largely upon the sediment contained in the dregs, 

 which may be both animal and vegetable in its character, but more 

 frequently vegetable, as it is composed of the bits of decaying nipa form- 

 ing the roofs from which the rain water is collected. 



The larvffi, in feeding, move forward over the bottom of the vessel, 

 taking in the particles of food with great rapidity and rejecting tiny 

 morsels of undesirable material in a constant stream. 



The larval period lasts from five to eight days. 



Pupa: The pupa measures 6.5 millimeters over the dorsum. It is gray when 

 newly transformed, but soon turns to an almost black-brown, the markings of 

 the adult showing plainly after the second day. The pinnurte are thickly clothed 

 with fine hairs, their entire margins being likewise so adorned. The urochaetie are 

 perfectly straight and are one-fourth tlie length of the pinnuroe. A single, very 

 large, simple bristle projects from the postero-lateral angle of the eighth segment, 

 while a few others are found on the posterior dorsal and ventral areas of the 

 remaining abdominal segments. 



