121 



of water that may prove suitable breeding places, the destruction of 

 existing breeding places and measures to prevent oviposition in waters 

 that cannot be removed. 



The work carried out on these lines during the campaign in Alsace 

 is described. Owing to the abundance of Anopheles rnaculipennis 

 and A. bifurcatus in certain districts it was found necessary to include 

 destruction of the adults in the summer. This was effected by 

 spraying with " Floria-Insektizid," a substance that had proved most 

 effective in the winter control. During July a 10 per cent, solution 

 was used, but in the previous and following months 5 per cent, should 

 prove sufficient. 



In the second paper spraying is compared with the use of hydrocyanic 

 acid gas. Although the latter has proved most valuable in dealing with 

 many other pests, the author emphasises the advantages of spraying 

 in dealing with mosquitos. During the wititer a 3 per cent, solution 

 only is required to kill the adults. "All methods to be effective should 

 be systematically organised and carried out by the whole community. 



Teighmann (E.). Die Bekampfung der Fliegenplage. [The Control 

 of the Flv Pest.] — Zeitschr. f. angew. Entom., Berlin, iv, no. 3, 

 1918, pp. 347-365. 



Experiments made with M'lsca domeslica, Fannia (Homalomyia) 

 canicularis and Stotnoxys calcitrans show that these flies can be des- 

 troved by exposure for 30 minutes to 1 volume per thousand of 

 hydrocyanic acid gas (1-2096 grm. HCN per cu. metre) or for 15 

 minutes to 2-J- volumes per thousand (=3-024 gnns. HCN per cu. metre). 

 The early stages may be destroyed by the application of a solution 

 of sodium cyanide ait the strength of O'l per cent, for the eggs and 

 0-25 per cent, for the larvae and pupae. 



Prell (H.). Das Entstehen von Schnakenplagen. [The Origin of 

 Mosquito Plagues.] — Zeitschr. f. angeiv. Entom., Berlin, v, no. 1, 

 1919, pp. 61-66. [Received 19th April 1920.] 



As the occurrence has been observed of large numbers of certain 

 mosquitos such as Culex pipiens and C. hortensis {territans) without 

 man being attacked by them, it is suggested in explanation that a 

 change has taken place in their habits, though this theory requires 

 further proof. 



Teich^iann (E.). Blausaure-Verfahren und Winterbekampfung der 

 Stechmucken. [Hydrocyanic Acid Methods and Winter Control 

 of Mosquitos.] — Zeitschr . f. angew. Entom., Berlin, v, no. 1, 1919, 

 118-125. [Received 19th April 1920.] 



The value of hydrocyanic acid gas in controlling mosquitos [R.A.E., 

 B, vi, 57; vii, 126] has been confirmed by further experiments carried 

 out in cellars of inhabited houses. Details of the work are given. 



