THE MOSQUITOES OF THE SOUTHEASTERN STATES \\ 



The gum arabic is dissolved in the water, the action being hastened 

 by keeping the water warm, and the other ingredients are added in 

 the order given. The thick solution is then strained through three 

 or four thicknesses of clean muslin; if clear lumps of the gum have 

 been picked, the medium is then usually sufficiently cleared. _ Several 

 weeks are required for the mounts to harden, but the hardening may 

 be hastened by placing them in a warm incubator. The cover glasses 

 may be sealed by ringing with cellulose cement. In cold weather 

 white crystals may form in fresh preparations. To overcome this, 

 the substitution of glycerin for the glucose sirup has been recom- 

 mended. Larvae may be mounted in a chloral-gum medium direct 

 from water or from a preservative after rinsing in water. 



Suitable balsam mounts of entire larvae require somewhat pro- 

 longed dehydration and hardening in alcohol. 



For taxonomic study or for identification of species difficult to 

 determine, it is frequently desirable to have both the larval skin 

 and the adult of the same individual. For such rearings a nearly 

 mature larva is isolated in a separate dish, and when pupation occurs 

 the larval skin is removed with a pipette, spread out carefully on a 

 slide, and a mount prepared in the chloral-gum medium. The dish 

 or vial containing the pupa should be covered with cloth or a larger 

 dish or plugged with cotton, and after the adult emerges sufficient 

 time (about 24 hours) should be allowed for the sclerotin to become 

 thoroughly hardened, before it is killed. The specimen is then 

 placed in the collection with a number corresponding to that given 

 the larval skin. If a balsam mount of the larval skin is desired, the 

 specimen may be cleared on the slide with carbol-xylol or other 

 medium. 



Adult mosquitoes are usually collected while they are biting or 

 resting in secluded corners inside or underneath buildings, in tree 

 holes, etc. A chloroform killing tube (fig. 5) is convenient for this 

 purpose. It may be prepared by placing a half -inch layer of cut 

 rubber bands in the bottom of a large shell vial or test tube, saturat- 

 ing the rubber with chloroform, and covering with a plug of crumpled 

 paper and a circle of stiff paper or a layer of cotton. The writers 

 prefer a shell vial seven-eighths of an inch in diameter and about 5 

 inches long. When the tubes are kept tightly corked, the rubber 

 retains the chloroform for some time. As moisture is liable to con- 

 dense on the inside of the tubes, the dead mosquitoes should not be 

 left in them long. 



A pill box, with a thin layer of cotton pressed down into the 

 bottom and sides, is convenient for holding or shipping the speci- 

 mens. The box should not contain so much cotton that the specimens 

 will come in contact with the lid, and if more than a wisp is used 

 its weight will cause it to shift about in the box during shipment. 

 Cotton should not Jbe placed on top of the specimens. Specimens 

 that have been moistened, crushed, or rubbed are usually unsatis- 

 factory for identification. 



The suction type of light trap, as developed by New Jersey workers, 

 is being used extensively for obtaining samples of the mosquito fauna 

 of an area and records of the relative abundance of different species, 

 particularly in connection with control operations. The specimens 

 captured are more or less damaged, however, and usually unsuitable 



