24 MISC. PUBLICATION 336, U. S. DEPT. OF AGRICULTURE 



the different parts of the body. Illustrations are provided herein 

 to show the names and locations of the principal parts that are uti- 

 lized in this connection, and the diagnostic keys have been made as 

 simple and as nearly self-explanatory as accuracy will permit. 



For the examination of the external characters of adult mosquitoes, 

 a binocular dissecting microscope is necessary for satisfactory work. 

 It should be provided with objectives and oculars giving magnifica- 

 tions up to about 85 X. (Higher magnifications are sometimes 

 needed.) With high magnifications a spotlight or other source of 

 bright illumination is required. For the examination of larvae and 

 slide mounts of male terminalia, a compound microscope is needed 

 and should be equipped for magnifications of about 100 and 400 X. 

 The oil-immersion objective is not ordinarily required, except for 

 advanced work on the male terminalia. For field work and for pro- 

 visional identification of adults, a good hand lens giving a magnifica- 

 tion of 10 to 15 X is very useful. In fact, after one has become 

 thoroughly familiar with the species of a locality, he will be able to 

 identify many of them with the hand lens, and some of them even 

 with the naked eye. 



Workers inexperienced in systematic work with mosquitoes should 

 have on hand, for comparative study, at least a small series of cor- 

 rectly identified species, which can be obtained by sending material 

 to a specialist with the request that named specimens be returned. 

 Until one has become thoroughly familiar with the species, the 

 material should in any case be forwarded to an authority for a check 

 on the identifications when questions of control or information on 

 habits are involved, since misidentifications are liable to result in 

 serious difficulties. Identifications may be obtained through the 

 Bureau of Entomology and Plant Quarantine and in some of the 

 State universities and experiment stations. 



MOSQUITO CONTROL 



Antimosquito work may be undertaken either as a means of con- 

 trolling mosquito-borne diseases or purely to eliminate annoyance. 

 Although the former is regarded as the more important, the fact 

 should not be overlooked that mosquito annoyance not only is a detri- 

 ment to health and happiness but results in a direct economic loss 

 by reduction of property values, injury to livestock, expense of pro- 

 tective measures, and in other ways. These losses frequently are 

 much greater than the cost of mosquito control. 



Nearly everyone is familiar with the efforts made to eliminate 

 mosquito -breeding places and with the use of larvicides in antimos- 

 quito work. The practical phases of the problem, however, form a 

 large specialized subject, and a general summary only will be given 

 here, with reference to underlying principles and to the practices and 

 materials that have become more or less standardized or are of recent 

 development. 



MOSQUITO SURVEYS 



Mosquitoes have extremely diverse breeding habits, particularly 

 in respect to the type of place selected for oviposition. Because of 

 this diversity the species to be dealt with and their individual habits 

 must be known before control measures can be applied intelligently. 



