153 



other than G . palpalis, and " iSlotnoxi/s or evoii MoscjuitocH . . . iji 

 rare instances " may act as transmitters, until there is more reason 

 to suspect these flies than at present exists " they may be for 

 practical purposes neglected."* 



Summarising what has been stated above, it may be regarded as 

 proved that Stomoxys calcitrans, L., as also 8. nigra, Macq., and 

 probably other species of the genus can convey trypanosomes 

 directly from an infected to a healthy animal, when the bites follow 

 one another immediately. On the other hand, the evidence tends 

 to sliow that, when the interval between the bites is longer (the 

 maximum period within which a bite is infectious has not yet been 

 determined), although active trypanosomes may be present in 

 the intestine of the fly its bite is innocuous. There is no indication 

 that trypanosomes ingested by S. calcitrans pass through a 

 developmental cycle, and they apparently disappear within forty- 

 eight hours. With regard to diseases other than trypanosomiases, 

 there are some grounds for tliinking that 8. calcitrans, like other 

 biting flies, may occasionally disseminate the bacillus of anthrax, 

 and, in Europe, it would appear that the fly is the intermediate host 

 of a species of Filaria parasitic in cattle. 



Stomoxys nigra, Macquart. 



Dipteres Exotiques, 4e Supplement, p. 239, Tab. 22, fig. 5 (1850) : 

 Memoires de la 8ociete Nationale des 8ciences, de V Agriculture 

 et des Arts, de Lille. Annee 1850. P. 212 (Lille, Paris, 1851). 



Plate XIII., fig. 101. 



As already stated at the commencement of the notes on the 

 foregoing species, 8tomoxys nigra, Macq. (of which 8. glauca, Griinb., 

 is a synonym), and 8. calcitrans, L., are by far the most widely 

 distributed representatives of their genus in Africa. In many 

 localities the two species occur together, and though it is possible 



* Sleeping Sickness Bureau, Bulletin No. 2, p. 72 (December, 1908). 



