141 



157, and 157. The e^gs from these retarded ovipositions seem as 

 numerous as in normal cases. The third tick in the above series 

 laid 8,307 eggs, a figure inferior to the average of 10,000-15,000 given 

 by Nuttall, but larger than that of 4,300 found In' that worker_ for 

 ticks from Algeria. The series was kept at a temperature of 19'-25°_C. 

 (59°-77'' F.),so that lack of warmth is no reason for the delay. Nor 

 can lack of food be adduced. 



In any case all measures directed towards the destruction of H. 

 ae^vpliiim must have regard to the possibility of a long preoviposition 

 period. Pasture rotation, already of doubtful efficacy owing to the 

 long resistance offered by the larvae to starvation, is now faced with 

 this fresh difficulty. 



Hkarle (E.). The Mosquito-control Act of British Columbia.— .4°^^ /r. 



JL, Victoria, B.C., vi, no. 4, June 1921, p. 98. 



This Act, passed in 1919, has just been repealed as a result of data 

 collected by the author, who was the Federal Officer studying mosquitos 

 in the Fraser Valley. The Act authorised the formation of locahsed 

 mosquito-control districts with funds derived from a municipal tax 

 on real property, and such legislation would be admirably suited to 

 cope with certain mosquitos where the trouble was caused by general 

 breeders with a small range of flight. In the Fraser Valley, out of a 

 mosquito fauna of over twenty species, only two are of economic 

 importance, and these only occurred in great numbers when the 

 river freshets exceeded certain levels. 



Little real progress in controlhng these mosquitos can be expected 

 until the larger areas subject to flooding have been reclaimed. Once 

 the reclamation of these is completed, it will be feasible to deal with 

 the smaller ones by artificial methods. There is little hope of much 

 being accomplished until the municipalities and other bodies in the 

 affected region co-operate and vest their authority in a central mosquito- 

 control commission. 



Webb (J. L.). Arsenical Poisoning of Stock.—//. Dept. Agric. Union 

 S. Africa, Pretoria, ii, no. 6, June 1921, pp. 5o7-561. 



Dipping in arsenical fluids has entailed an occasional loss of farm 

 stock from poisoning, which is avoidable in many cases. The most 

 common causes are : dipping solution made too strong ; dipping on 

 misty or wet days, or through such weather coming on after animals 

 have been dipped ; working cattle during the heat of the day that 

 are being regularly dipped in full strength solution every five or seven days 

 and continuing to work them after they show signs of distress ; leaving 

 dips exposed to the access of stock ; drinking dip during the process 

 of dipping ; too frequent dipping or spraying ; and the malicious 

 poisoning of cattle with arsenic. These points are discussed and 

 the symptoms of arsenical poisoning and post-mortem appearances 

 are described. 



The best chemical antidote is ferric hydrate. This may be prepared 

 by diluting 3 oz. of tincture of iron perchloride with 4 oz. water ; 

 dissolve 1 oz. sodium carbonate (washing soda) in | pint of water ; 

 mix the two solutions and administer. These quantities will render 

 insoluble 10 grains of arsenic. Three doses at least should be given, 

 repeated at intervals of a quarter of an hour. The above doses are 

 for horses or cattle. To be of any use the antidote must be adminis- 

 tered within a very short time of the poison being taken, and in animals 



