14 



Trari^^fer nf the J Ace hy Flies. 



The carabao louse lias been found attached to the legs of a 

 species of Lyperosin, common in the islands, on an average of 

 one in three, 1,800 flies collected in five days yielding 620 lice. 

 This lasted till the middle of MarcK, when the Lyperosia 

 gradually disappeared and the stable-fly, Stonwxys calcitrans, 

 predominated in vast numbers. The louse was never found 

 attached to the latter nor indeed to any other species than the 

 Lyperosin. The parasite in question was undoubtedly the larval 

 form of the carabao louse. No other species was collected from 

 carabao on which the infested flies were found. None of the 

 lice found on the flies had imbibed mammalian blood. How far 

 the flies may act as distributors of the lice is unknown, but 

 it seems probable that they can and do act as such. 



An Experivient to demonstrate Periods of Non-infectivity in 

 Carahaos ajfected with Surra. 



An emulsion of 150 Lyperosia sp., which had bitten a surra 

 carabao on a day when its blood was negative, when injected 

 into a horse and two guinea-pigs gave no reaction, but an 

 emulsion made from flies collected on the same carabao when 

 positive gave a definite surra reaction. The author argues that 

 if the blood of the animal had been used in place of the fly 

 emulsion the result would have been the same. From the 

 results of a number of experiments in blood inoculation the 

 author concludes that, (1) during the negative stage of the disease 

 the carabao is not a source of danger as an active focus for fly 

 dissemination ; (2) it does not become imperative to verify micro- 

 scopical findings (when carefully performed) by animal inocula- 

 tion in suspected cases of surra in carahaos, for it is not convincing 

 or significant during negative periods ; (3) when the trypanosome 

 is not found during protracted stages upon microscopical examina- 

 tion it should not be ossumed that the nnimnl is free from 

 infection. 



Ento77ioloc/iral stvdy of a Si/rra Outhreak among Carahaos la 

 the region of La> Carlotta, Occidental Negros. 



Investigations at 7 haciendas : — 



(1.) 105 cattle, 115 carahaos, 6 horses; all permitted to pasture 

 together freely; 8 cases carabao surra and 1 bullock, horses free. 

 Over 80 per cent, of the flies found were common to all three 

 Ivinds of animals and Avere all Lyperosia. 



(2.) 90 cattle, GO carahaos; 1 horse affected with surra, but 

 had come from a farm close by only 4 weeks before. The flies 

 collected were all Lyperosia; no Stomoxys whatever. 



(3.) Indo-Chinese bull badly infected, 50 carahaos, in same 

 pasture, free; few Stom,oxys, dense swarms of Lyperosia around 

 tbe bull, which also yielded carabao lice. 



