157 



its base and about 1/40. near its extremity. The point is shaped like that of 

 a writing pen, its edges being provided with ten or twelve sharp teeth 

 decreasing in size as they reach the finely pointed extremity. The shaft 

 presents transverse serrated ridges, which must act somewhat like the teeth 

 of a conical file ; these ridges, as well as the terminal teeth, belonging to the 

 mandibles which are closely applied upon the sides of the labrum. 



The sting remains enclosed in a brown, hairy sheath, excepting when 

 it is introduced into the skin; during this operation, the sheath, which is 

 slit in front to within a short distance of its point, bends backward and the 

 sting appears like a fine wiry lance. This generally penetrates to a depth 

 of from IV2 to 2mm. before a blood vessel is reached of sufficient calibre to 

 allow blood to be drawn. The insect requires from one to five or seven 

 minutes to complete this operation. "When once it has fairly implanted its 

 sting, the mosquito can be easily covered with a glass tube or phial and 

 imprisoned. I have generally resorted to this means in order to procure live 

 specimens, so as to be sure of their efficacy for my experiments. 



The C. mosquito is diurnal and crepuscular, making its appearance 

 early in the morning, again between 9 and 10 A. M., and in the afternoon 

 until night. Stragglers may be met as late as 10 or 11 P. M., and in close, 

 dark rooms they are generally felt or heard throughout the day (in 

 summer). The males are the first to make their appearance, apparently 

 attracted by the emanations of human perspiration from the body or from 

 worn clothes; they keep flying about until the females appear, and it is 

 only after pairing that the new females are able to sting and draw blood. 

 When caught as they emerge from their pupa case, they often attempt to 

 do so, but their proboscis bends, either from want of rigidity of the sheath, 

 or from some obstruction at its point, and the lance fails to pierce the skin. 

 Immediately after pairing, however, the insect is ready to sting. 



I have found no difficulty in getting this species to do so as often as 

 it has completed the digestion of the blood previously sucked, but not 

 before an interval of from two to five days (according to the season and 

 weather), when the insect had been able to fill itself completely. As a proof 

 of the remarkable resistance of this insect to rough usage, and in 

 order to exemplify some of its habits, I copy the following record from my 

 note-book : 



January 13, 1881. A fresh female C. mosquito was caught in the 

 afternoon and allowed to fill with blood off my hand, being retained 

 captive in a glass tube closed with a muslin cap. 



15th. Filled again from my hand, biting through the muslin cover. 



16th. Strong and active; still distended with blood, refuses to sting. 



17th. Stings my hand readily through the muslin and fills. 



18th. Though still retaining some blood, bites my hand readily 

 through the muslin. Two hours later, not having apparently taken its 



