18 American Midland Naturalist Monograph No. 3 



cover slip with a dissecting needle. Transfer the slide to a compound micro- 

 scope and examine the crushed glands and adjacent fluid under high-dry 

 magnification The sporozoite<: are minute, glistening, slightly curved rods. 



The technique of making permanent mounts of mid-guts and salivary 

 glands is given by Wilcox and Logan (187). 



Collecting Mosquito Eggs 



It has become a generally accepted fact among mosquito workers that 

 the study of mosquito eggs, in conjunction with other stages in the life cycle, 

 is of much value. It may be of special importance when dealing with closely- 

 related species. The importance of the study of mosquito eggs is clearly 

 shown by Hackett and Missiroli (72) and Bates (12) in their works on the 

 taxonomic status of the mosquitoes of the Anopheles malcupennis complex. 

 Egg rafts of many species of Culicines are frequently encountered in the field 

 and can be gathered and carried to the laboratory for hatching and rearing. 

 Eggs of Anophelines may be collected in the field by placing a white muslin 

 bag over the hand and sweeping the hand through the water in spots where ovi- 

 position is likely to have taken place, or water can be taken with a dipper 

 and poured through the muslin. Muslin fitted on embroidery hoops may 

 also be used for this purpose. The cloth should be carefully examined with 

 a hand lens at frequent intervals for the detection of eggs. Eggs of certain 

 species of Aedes and Psorophora may be obtained in soil scraping from 

 likely breeding spots and hatched in the laboratory. 



Gravid females may be captured and isolated for oviposition in small 

 cotton-stoppered, flat-bottomed shell vials. Many species of Aedes, Psoro- 

 phora and Anopheles will usually oviposit on cellucotton which has been 

 tamped firmly into the bottom of the vial and saturated with water. When 

 eggs are obtained from an ovipositing female in an isolation vial and are 

 hatched and reared, one can study and correctly associate all stages of a 

 species. In addition, this method of collection and study furnishes valuable 

 information on the bionomics of the less common species. 



Collecting Larvae 



Mosquito larvae may occur in all types of waters, varying from large 

 lakes and marshes to small collections of water in tree holes, leaf axils of 

 plants and artificial containers; therefore in making an initial survey of mos- 

 quito breeding in an area, every possible type of breeding place should be 

 examined. A careful study of the different factors present in each breeding 

 place should be made to determine, if possible, the breeding preferences and 

 requirements of the different species. The association of a species of mos- 

 quito with certain characteristics of the breeding place is helpful to the col- 

 lector and is of practical value to the control worker. 



A uniform system of larval collections or inspections should be instituted 

 as a part of every mosquito-control project to provide the following infor- 

 mation: (1) The areas producing species of economic importance; (2) the 



