212 



an otherwise imexpiaiued fact, that although saiid-flies trouble 

 man durino- the hot weather and rains, yet females of P. minutus 

 gorged with apparently fresh blood can be found without much 

 difficulty from November to May, a period during which the 

 human subject is never attacked. The result of the examination 

 of blood in the bodies of 40 specimens of P. minutus between 

 25th April and 5th May show that 11 contained human blood, 24 

 lizards' blood and 5 doubtful. It was assumed that nucleated 

 corpuscles were those of a lizard. The author says that flies 

 have been seen by himself on one occasion biting another species of 

 lizard and on two other occasions on the head of a common toad. 

 It appears to be possible that these other reptiles afford food for 

 the flies as well as the gecko. 



/ MiTZMAix (M. B.). The Surra-Conveying Fly of the Philippines 

 )( and some factors concerned in Control Measures. — Philippine 



Agric. Review, Manila, vi, no. 8, Aug. 1913, pp. 3T1-3T9. 



The author points out that Bagshawe has indicated that it is 

 possible that an epizootic of surra may be started from an animal 

 in whose blood trypanosomes are scarce. If it were known that 

 one species of insect only is capable of becoming infected from 

 such a host and that flies of this species transmit infection to other 

 animals for a period of many weeks, such knowledge could not 

 fail to lead to economy in preventive methods. 



The author's studies of surra in the Philippines lead him now 

 to the opinion that Stomoxys calcitrans, L., has little or nothing 

 to do with the transmission of the disease, but that Tahanus 

 striatus, F., the common horse-fly of the islands, is the carrier. 

 The breeding places of this fly have now been located on the 

 shore of Laguna de Bay. 



The food of the larvae consists not only of the minute Crustacea 

 of the lake, but principally of the larvae of the Muscid flies laid 

 in the carabao manure on the swampy land which is cultivated by 

 the lake-shore. In several cases Tabanid larvae have been seen 

 buried in the dung in search of food. The habits of the larvae 

 are described elsewhere (see this Review, Ser. B. I, p. 200). 



Apparently spontaneous cases of surra, observed late in 1911 

 and early in 1912, gave rise to the suspicion that Tahanus had 

 something to do with the transmission of the disease, but 

 Stomoxys, Lyperosia, Hippohosca, mosquitos and midges were 

 present in such numbers that they could not be regarded as 

 negligible factors. Stomoxys, Lyperosia and Hippohosca have 

 now been investigated from the standpoint of mechanical trans- 

 mission and may be eliminated. The mosquitos, which have been 

 studied more or less thoroughly in Africa and India in relation 

 to the disease, may also be eliminated, the writer having been 

 able to confirm the negative results obtained by others. Midges 

 {Chieonomidae) are often present among the draught animals of 

 the Philippines in enormous numbers and in the author's opinion 

 may still be under suspicion, although workers in Africa and 

 India regard them as of no serious consequence in disease trans- 

 mission. _ 



