115 



except in small flocks. Spraying \nth poisonous dips at intervals 

 of 3 inoitlis, with a pressure of not less than 120 lb. per square inch 

 has given good results, it having been found that with a race 3 ft. 

 wide and 50 ft. long, 3 men are able to treat about 2,000 sheep a day. 

 Adult flies are held in check by means of traps and poison baits and 

 by insectivorous birds, and the larvae are devoured by mice and are 

 parasitised by Chalcids. Arsenic in its crude form is effective for 

 killing both the fiies and the maggots, but care is necessary in its use 

 owing to its little-known effect upon the health of the sheep. An 

 arsenical dip in use for over 30 years in England and consisting of 

 white arse! ic 50 lb., caustic soda 4 lb., carbonate of soda 20 lb., 

 soft-soap 35 lb., sulphur 30 lb., water 25 gal ., one gallon of which 

 mixed with 59 gals, water forms a one-minute dip, has, on one occasion, 

 been known to kill a large number of sheep. Sheep with 2 months', 

 6 months' and 8 months' wool dipped twice and thrice in a poisonous 

 dip came through the fly se son well and yielded a good fleece. It 

 is believed by many that flies are very local, but they are known to 

 follow sheep into a fresh paddock, though they are generally picked 

 up by the sheep in can ping places, water-holes, shearing-sheds, lamb- 

 marking yards, etc., where they breed. Nothing has, as yet, been 

 found, either poisonous or non-poisonous, which \^^.ll prevent flies 

 from attackmg sheep. The health of the sheep has h marked influence 

 on the incidence of the maggot-fly, and for that reason all sick sheep 

 should be isolated from the flock when flies are active, and sheep 

 suftering from internal parasites should be regularly treated. Density 

 of wool, when excessive, seems to be a pre isposing cause of fly-attack, 

 since crossbreds do not suffer nearly so much as merinos in this respect. 

 In regard to sex, maiden ewes in every breed are the most susceptible 

 animals. The order of the seasons in which sheep are most liable to 

 attack are : — Spring, autumn, wet mnters and summer. In dry 

 weather the flies are little in evidence. 



The information contained in this paper has been previously dealt 

 •with [see this Review, Ser. B, i, p. 115, iii, p. 158, v, p. 173, vi, pp. 14, 

 142!. 



GuiTEi (F.). La Station entomologique de la Facuite des Sciences de 

 Rennes en 1917. — Inseda, Rennes. viii, 1918, no. F5-96 pp. 177- 

 181. [Received 29th April 1919.]' 



The Argasid tick, Ornithodorus coniceps, is reported from the Depart- 

 ment of Aude, and is recorded for the first time as biting man in 

 France. During the years 1915-1917, leaflets concerning insects 

 injurious to troops in the field have been constantly disseminated 

 among the arnw, and large quantities of sublimated sulphur for use 

 agair st Pediculus humanus {vestimenti) were distributed. 



