Carpenter et al.: Mosquitoes of Southern U. S. 11 



two persons, one collecting from the other, or by one person collecting alone. 

 In the latter case, it is best for the collector to be seated with his sleeves 

 rolled above the elbows and his trousers rolled above the knees. The collector 

 should sit quietly and capture the specimens with an aspirator or a chloroform 

 tube as they alight or begin to feed. A flashlight may be used, but the amount 

 of light should be reduced by removing the lens or covering it with a semi- 

 transparent paper. The collecting at any one place should be done for a set 

 period, usually 20 or 30 minutes. In a malarious area, this type of human 

 exposure is to be discouraged. 



Many woodland species, particularly Aedes and Psorophora, may be cap- 

 tured during the daytime in thickets, woodlands, and on occasions in open 

 areas, while attempting to bite. The same method given for making night- 

 biting collections is used except that the flashlight is not needed. 



Sweeping Vegetation. — Certain species of mosquitoes, particularly Aedes 

 and Psorophora, in this region are seldom encountered in resting stations, 

 but shelter during the day amongst the vegetation in moist, shady places, 

 and especially near the water in which they breed. Mosquitoes can be cap- 

 tured in situations of this kind by sweeping with a net or by disturbing them 

 and catching the specimens in the net while they are in flight. It is frequently 

 advisable to sweep the vegetation around the margins of a breeding place 

 in order to obtain adult specimens which may have recently emerged. Male 

 specimens of species seldom obtained by other collecting methods are occa- 

 sionally taken by this latter procedure. 



Equipment. — A chloroform killing tube (Fig. 4, B) can be made from a 

 large cork-stoppered shell vial or test tube about 1 inch in diameter and 

 6 or 8 inches long. The tube can be prepared as follows: Cut a scrap of 

 old auto innertube into enough small cubes to occupy the bottom linear 

 inch of space in the tube (rubber bands may be substituted if desired) . 

 Pour chloroform into the tube until level with the top of the layer of rubber. 

 After the chloroform has been absorbed by the rubber, a plug of tissue 

 paper should be packed tightly into the tube and covered with one or two 

 close-fitting circular sections of blotter or cardboard. To recharge the tube, 

 remove the blotter or cardboard discs and tissue paper and add chloroform 

 to the rubber as before. Cyanide may be used in the killing tube instead of 

 rubber and chloroform, but should be handled with caution since it is 

 extremely poisonous. 



An aspirator (Fig. 4, D) is a convenient device for collecting mos- 

 quitoes in diurnal shelters or while they are biting or attempting to bite. 

 The aspirator is made from a piece of glass tubing about 1/2 inch in diam- 

 eter and about 6 inches long, fitted with a piece of rubber tubing about 

 30 inches long. A chemical test tube with the bottom end cut away makes 

 a satisfactory tube. A cloth screen is held in place in the base of the glass 

 tube by a cylindrically-coiled flexible card. Captured mosquitoes are blown 

 from the aspirator into a small cage or directly into a killing tube. 



A folding midge net 8 inches in diameter when open, with a short 



