Carpenter et al.: Mosquitoes of Southern U. S. 23 



taken from water and placed directly in the PVA-Iacto-phenol medium for 

 mounting. It is often necessary in thick mounts to add more of the medium 

 at intervals while drying. The mount will be cleared and the cover slip 

 firmly glued in place within 2 or 3 days. 



Mosquito Identification 



The identification of adult and larval mosquito specimens requires a 

 knowledge of morphology; suitable equipment, including microscopes and 

 microscope lamps; and diagnostic keys or descriptions in which all the species 

 in the area are included. This publication contains keys, descriptions, and 

 illustrations dealing with the principal structures used for determining the 

 identity of the different species occurring in the southern United States. 



A wide-field dissecting microscope equipped with low, intermediate and 

 high-power objectives is satisfactory for identifying adult mosquitoes and 

 most larval specimens. Frequently a compound microscope with a higher mag- 

 nification is necessary for more detailed larval study and for the examination 

 of male terminalia. 



The light from a flexible-arm desk lamp, condensed by a 1 -liter Florence 

 flask filled with water, is satisfactory for use with a dissecting microscope, 

 although other types of microscope lamps may give good results. For use with 

 a compound microscope, the writers prefer a flexible-arm desk lamp as 

 described above but without the water-flask condenser. 



An experienced technician will soon learn to identify adult mosquito speci- 

 mens in the pill box in which they were stored at the time the collection was 

 made, providing they are not overcrowded. The transfer of individual speci- 

 mens from pill boxes to the stage of the dissecting microscope requires consid- 

 erable time and often results in breakage. Some workers prefer transferring 

 all the specimens of a single collection to a petri dish lined with white paper; 

 as each specimen is examined and identified, is is moved to one side with a 

 pair of forceps. When identifying large numbers of specim.ens in this manner, 

 much time can be saved if two persons work together, one identifying the 

 specimens and the other recording the data. 



When unmounted larvae are to be identified with a dissecting micro- 

 scope, it is best to place them in a Syracuse watch glass in either water or the 

 preserving fluid. Light from the flexible-arm desk lamp can be sharply focused 

 by means of the water-flask condenser and the specimens may be manipulated 

 as necessary with the aid of a dissecting needle or small camel's hair brush. 

 All but the most minute structures are visible under the high power of the 

 dissecting microscope when this method of examination is employed. 



Characters Used in Identification 



Adult Characters 



The body of an adult mosquito, as in other insects, is divided into three 

 well-marked regions, the head, the thorax, and the abdomen, each of which 



