198 



of this medium and the conditions of its infestation by flies. Manure 

 not more than 24 hours old produces, during the warm months, an 

 average of 10,000 to 12,000 flies per cubic metre. It is estimated that 

 one horse can produce sufficient manure to give rise, in summer, to 

 from 40,000 to 50,000 flies a month. Fresh manure alone is suitable 

 for breeding ; egg-laying takes place in the stable, on the dung 

 impregnated with urine. Fermentation, which sets in after about 

 24 hours, prevents oviposition. Antiseptic substances and larvicides 

 (borax, solutions of cresyl, ferrous and ferric sulphates), by decreasing 

 the rate of fermentation, can prolong the normal period of oviposition 

 by 1 or 2 days. These substances therefore give a result opposite to 

 the one required by increasing the chances of infestation of the manure. 

 After the 6th day., the manure heap no longer contains larvae, since 

 these have migrated to the edges to pupate. Control measures should 

 thus be taken during the 5 days which follow removal from the stable. 

 The heat of fermentation of a manure heap can be used for the 

 destruction of the contained larvae. The larva, submitted in the 

 manure to a temperature of 50° C, and protected from the gases 

 resulting from fermentation, dies in 3 minutes ; in direct contact with 

 the gases, it dies in 1 minute at 51° C, and in 4 or 5 seconds at 60° C. 

 If the manure be turned over, larvae which fall into the hot parts of 

 the interior are killed instantly. This practice, if carried out during 

 the first 3 days, would result in the destruction of 90 per cent, of the 

 larvae. The operation is rendered easier if the manure coming from 

 the stable be treated directly with the heat of fermentation of a heap 

 already formed. The fresh manure should be covered by a layer of 

 hot manure about 20 cms. in thickness ; the heat is then readily 

 communicated to the fresh material, in which the eggs are killed before 

 they can develop and the fresh material is also protected against 

 further oviposition. This biological method of destroying larvae by 

 heat is equivalent to an accelerated and total heating of fresh manure 

 up to 50° or 60° C, carried out without the expense of any combustible 

 material. 



RoDHAiN (J.) & Bequaert (J.). Sur quelques Oestrides du Congo 

 (Communication pr^liminaire). [On some Oestrids from the Congo 

 (Preliminary Note).]— 5w//. Soc. Path., Exot., Paris, viii, no. 7, 

 1915, pp. 452-458. 



The authors are preparing a memoir on this subject, but as it will be 

 some time before this is published, they desire to put on record the 

 principal results obtained. The larva and imago of Rhinoestrus 

 phacochaeri, sp. n., found in the skull of Phacochaerus aethiopicus, Pall., 

 are described. Imagines of Oestrus aureo-argentatus, Rodh. and Beq., 

 have been reared from larvae found in Buhalis lelwel jacksoni, Thorn., 

 and from the same antelope the larva of Oestrus bertrandi, sp. n., is 

 described, the adult being still unknown. Other species described 

 are : — -the larva and adult of Gedoelstia paradoxa, sp. n., also from the 

 same antelope and from Damaliscus korrigum jimela, Matsch., larva 

 and adult of Kirkia ? blanchardi, Ged. and K. tninuta, sp. n. The 

 paper concludes with an account of the distinctions between the larvae 

 of the genera concerned. 



