65 



occidentalis breeds mainly in clear pools with abundant vegetation 

 and open to sunshine; A. punctipennis apparently prefers quiet, 

 shady pools, and A. psendopunctipennis clear, shallow pools along the 

 edges of receding streams. A. qiiadrimaculatus occidentalis invades 

 houses, and is therefore of greater importance as a malaria carrier, 

 while A. pitnctipennis bites chiefly out of doors. The males of these 

 species disappear about the middle of November, and reappear in 

 the following year during the last week in April. A . quadrimaculatus 

 occidentalis passes the winter in the adult stage. Egg-laying begins 

 in the warmer days of February and March. It is advised that anti- 

 mosquito operations should begin in the autumn with a strong intensive 

 campaign to eradicate the last brood, and be followed by another early 

 spring campaign to eliminate the first brood. 



Freeborn (S. 11). The Seasonal History of Anopheles occidentalis 

 D. & K., in California. — Jl. Econ. Ent., Geneva, N. Y., xiv., 

 no. 5, October 1921, pp. 415-421, 1 fig. [Received 13th January 

 1922.] 



Anopheles quadrimaculatus occidentalis hibernates in California 

 in the adult stage from about the middle of November. Hibernation 

 is not complete, as the females sometimes change their places of refuge 

 during the winter. They begin to emerge in February, but have 

 practically disappeared by the end of that month. During the emer- 

 gence flight the area infested is almost always greater than at any 

 other period of the year, many districts being invaded that are free 

 at other seasons. This unusual extent of flight is probably connected 

 with the spread of the species. Females dissected during the winter 

 and at the start of the emergence flight contained half-developed eggs. 

 Those of unfed migrants became mature in about 48 hours after a 

 blood meal in the laboratory, and it appears that the overwintering 

 females lay only a single batch of eggs before they die. The adults 

 arising from these eggs in May and June are relatively few in number. 

 This may be due to the small number of eggs deposited or the exposure 

 of the larvae to predacious enemies during a period prolonged as a result 

 of the low temperature. Eggs are deposited by this generation a 

 few days after emergence. Under laboratory conditions not more than 

 three batches of eggs were ever laid, the total number being 499. 



A. quadrimaculatus occidentalis has been successfully controlled 

 in California by directing operations against the larvae after the 

 spring migratory flight of overwintering adults and again in the 

 autumn. By starting the work at a very early date absolute control 

 was obtained by midsummer, and fully half of the sum allotted for 

 this purpose, which was the same as in previous years, remained 

 unspent. The same measures would control A. punctipennis and 

 A. pseudopunctipennis, should they be found to hibernate in the 

 larval stage. 



Barber (M. A.) & Hayne (T. B.). Arsenic as a Larvicide for Ano- 

 pheline Larvae. — Public Health Repts., Washington, D.C., xxxvi, 

 no. 49, 9th December 1921, pp. 3027-3034. 



The authors confirm the work of Roubaud, who successfully used 

 trioxymethylene in poisoning Anopheline larvae [R.A.E., B, viii, 

 166, 167j ; m endeavouring to obtain some cheaper and more poisonous 

 substance they found compounds containing arsenic most promising, 

 Paris green proving the most effective. 



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