Culicidae 377 



successful maintenance of a colony of A. punctipcnnis. A limited success 

 has been achieved in the culture of A. crucians sufficient to learn that some 

 of the procedures necessary to the rearing of A. quadrimaculatus and 

 A. punctipcnnis must be more or less modified for this species. 



Colonies have been started by the collection of ova from gravid wild 

 females confined in small cages above dishes of water. These were given 

 a blood meal every three days as long as their ova were required. 



In the insectary a large tank raised 2 feet from the floor is maintained 

 as a balanced aquarium filled with water to a depth of 6 inches and 

 stocked with aquatic vegetation and snails. Normally the water is never 

 changed, though more is added as replacement is necessary to maintain 

 the proper level. A small handful of hay is placed in it once a week, as a 

 source of food for the snails. A small amount of lime water is added once 

 a month to provide calcium for them, and about 5 grams of ammonium 

 nitrate in solution is added twice a year as an extra source of nitrogen for 

 the aquatic plants. The aquarium attracts the female mosquitoes as a 

 place for oviposition. Oviposition is most abundant along the edges and 

 where the horizontal vegetation breaks the surface film. The space be- 

 neath the tank serves as a dark, humid diurnal shelter for the imagines.* 



In routine insectary operations, ova are collected from the aquarium by 

 skimming the water surface (which is an egg trap for ovipositing females) 

 with a cereal bowl. Before skimming, the bowl should be wet to prevent 

 the ova from sticking to the sides. The ova are dipped from the bowl 

 with a bent spoon, and poured into a folded paper in a funnel. After the 

 collection has been made, any larvae present are removed with a pipette, 

 and the ova are washed to the bottom of the filter cone by a gentle stream 

 of water. 



The surplus ova are stored in a Frigidaire at the laboratory for 2 weeks, 

 as an insurance against any accident. The moist paper filters bearing the 

 ova are kept in % P mt fruit jars. 



As required but before the end of two weeks the ova are taken from the 

 Frigidaire and returned to the insectary to be incubated. The ova are 

 washed from the filter paper by means of a pipette into the space within 

 a cork ring floating in a small bowl of water. The cork ring prevents 

 them from stranding on the sides of the bowl as evaporation lowers the 

 water level. They are incubated by floating the bowl in the aquarium in 

 the summer, and in the water bath with a temperature of 70 F. in the 

 winter. They should be kept in the bowl until they enter the second 

 stage, and during this period are fed only on yeast. 



In the outdoor insectary optimum temperature is provided by rearing 



* For further details of the construction and operation of the insectary see: Mark F. 

 Boyd, T. L. Cain, Jr., and J. A. Mulrennan: "The insectary rearing of Anopheles 

 quadrimaculatus." Amer. J. Trop. Med. 15:385, 1935. 



