20 American Midland Naturalist Monograph No. 3 



weather the corks or caps should be loosened occasionally to provide air. 



Collection Data. — Complete observations and field notes on all collec- 

 tions provide valuable information on breeding and other habits of mosquitoes. 

 The collector should not rely upon memory, but should make the notes at 

 the time of collection. Bottles in which larvae are collected should each be 

 given a collection number corresponding to a record kept in a field book. It is 

 preferable to place penciled collection data inside the larval container rather 

 than to use gummed outside labels which often become detached during 

 transit. 



Rearing, Storing and Mounting Larvae 



Rearing. — Larvae collected for rearing should be brought into the labor- 

 atory as soon as possible and transferred to jars or pans with sufficient water 

 surface for free movement and feeding. In rearing larvae, a large water sur- 

 face is necessary to provide proper aeration of the water, adequate feeding 

 surface for Anophelines, and to prevent overcrowding which may lead to 

 cannibalism. If possible, each rearing pan or jar should contain some of the 

 water and vegetation of the breeding place from which the larvae were col- 

 lected. It is often necessary to supplement the food supply by addition of 

 small portions of pulverized dog biscuit, Pablum, or yeast. If a consider- 

 able amount of evaporation takes place, fresh water should be added to the 

 pans. Larvae of large, carnivorous species should be isolated in small jars and 

 fed on larvae of some other species. Pupae should be transferred each day to 

 containers in emergence cages. 



When it is desired to associate larval and pupal exuviae with the adult, 

 single larvae are isolated in rearing vials. Shell vials measuring approximately 

 1 inch by 3i/2 inches are satisfactory for this purpose and should be properly 

 labeled and lightly plugged with cotton. The exuviae should be removed 

 with a pipette and preserved in 70 to 80 per cent alcohol, or mounted on 

 a slide and given a number corresponding to that of the emerged adult. 



Killing and Storing. — Full-grown larvae may be killed and preserved in 

 70 to 80 per cent alcohol or 10 per cent commercial formalin. Larvae retain 

 their form best if killed in hot, but not boiling water; but satisfactory speci- 

 mens are usually obtained if they are placed alive directly into the preserva- 

 tive. Another convenient method is to place a larva on a clean slide in a drop 

 of water and hold for a short period of time on the hot shade of a desk lamp. 



For shipping, larval specimens may be placed in small vials filled with 

 preservative and tightly corked. Large museum collections of larvae may be 

 preserved in small stoppered vials which are in turn stored in a larger con- 

 tainer filled with the preserving fluid. A label bearing the name of the species, 

 collection number, locality, date of collection and name of collector written 

 in pencil or India ink should be placed inside each vial with the larvae. 



Another satisfactory method of packing specimens for storage or for 

 shipping is to place them in dental procaine hydrochloride cartridges as 

 shown in Fig. 6. The empty cartridges, which are usually discarded by 



