213 



Tlie question is thus narrowed down to the Tahaims. One 

 species of Tahanus in Northern Africa is now known to be a 

 carrier of a form of trypanosomiasis closely resembling surra and 

 the fly has also been experimentally proved to carry surra in 

 India and in the Federated Malay States. The author says that 

 so far as Tabanids are concerned the carabao is the most favourite 

 animal, and that there is never any difficulty at the proper season 

 in catching- a large number on one of them, lie is also of opinion 

 that the body temperature of the animal is of some economic im- 

 portance, although the matter is at present in a theoretical stage. 

 Hewlett in India has endeavoured to demonstrate that mosquitos 

 are positively attracted by a temperature above normal. This 

 theory may be extended to the blood-sucking flies generally. It 

 has been specially noticed and confirmed by many investigators 

 that sick animals are more susceptible to the attacks of Stomoxys 

 than healthy ones, and this is especially the case with horses. 

 [This may be due merely to the fact that a sick animal may be 

 too listless to drive ofl the flies. — Ed.] 



Insecticides have been tried for the destruction of horse-flies, 

 but have proved more or less unsatisfactory. Substances acting 

 as repellents have given more favourable results, but direct 

 methods of destruction have proved unavailing. Hine has used 

 petroleum against Tahamis in the same way as against mosquitos, 

 and this method is supposed to be effective against the adult 

 flies which visit the water in order to drink. The same investi- 

 gator provides a most effective measure by gathering and 

 destroying the eggs, and says that in one liour 433 egg-masses 

 were collected, estimated to contain a total of over 108,000 eggs. 

 In the Philippines the only remedial measure used is the destruc- 

 tion of the adult flies, which are collected with a net or trapped 

 with tanglefoot applied to the trunk and larger branches of the 

 rain trees, which form their favourite resting places. 



Sick animals should be isolated and they, as well as healthy 

 ones, should be protected from flies ; screening, though not always 

 practicable, is a very valuable measure, but considerable pro- 

 tection can be obtained by the use of darkened sheds, or sheds 

 exposed to strong winds, and by building sheds and corrals some 

 distance from bodies of water. Animals at work or at pasture 

 may be covered with a protective wash. All sores and skin 

 abrasions of any kind should be kept covered with tar or some 

 other antiseptic greasy substance disagreeable to flies, both of the 

 blood-sucking and non-biting species. The author reconimends 

 that the roofs of animal sheds should be as low as the height of 

 the animals will permit, and in a stable of this kind in India, to 

 which he refers, during one entire surra season only two or three 

 Tabanids were found on animals. The removal of manure from 

 the neighbourhood of stables is of great value, although Tahanus 

 striatus does not normally breed in manure, and when larvae of 

 this fly are placed experimentally in great numbers in manure of 

 various kinds, they do not mature. Lime has been used with 

 effect to destroy larvae inhabiting the dung, and any means which 

 will provide for its rapid dessication is sure to be of value. 

 Eepellents and washes applied to the animal in the dry season 



