170 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XV 111, 



Habits of the perfect insects. — The flies of the sub-family Leptince, which 

 includes the genera Leptis and Symphoromyia, are somewhat sluggish, and are 

 fond of resting motionless and head downwards upon the trunks of trees in 

 shady places. Their flight is short and noiseless. 



Muscidse (Tsetse-flies, and their allies). 



In this family the blood-sucking habit is highly exceptional, and is confined 

 to a very few genera and species, all of which in appearance present a general 

 resemblance to the Common House-fly. In cases in which the blood-sucking 

 habit occurs, it appears to be common to both sexes. The following are the 

 blood sucking gerer.i of Muscidse hitherto described : Stoinovcys (with about a 

 dozen species ; this -genus is universally distributed, and it is possible that 

 several additional species have yet to be described) ; Lyperosia (•with two 

 species, one of which occurs in Europe -and North America, the other in 

 Somaliland ; three additional species, probably distinct and as yet undescribed, 

 are found in West Africa, Sokotra, and Ceylon) ; Glossinella (with one species 

 found in German East Africa) ; Hamatobia (with three species, 

 two European, the third fouud in Java) ; Beccarimyia (with a 

 single species, described from the neighbourhood of Massowah) ; 

 and Glossina, or Tsetse-flies (eight species, restricted to Africa 

 and Southern Arabia). In addition to the foregoing, represen- 

 tatives of two species for which a new genus will probably have to stomoxyg «/>., 

 be created have recently been obtained in West Africa and India. from Na,nl 



N.B. — In view of the near relationship between Slomoxys and attitude 



Glossina (Tsetse-flies), it is desirable that special attention should showing the 



be paid to the former in order to discover whether the species of f, 081 lon . 



the wings, 



this gtnus are capable of conveying any species of Trypanosoma* (k lj). 



Appearance. — As stated above, the blood-sucking Muscidse all present a 

 general resemblance to the Common House-fly, which, however, in the case of 

 Tsetse is obscured by the fact that the wings in the resting position (fig. 10), 

 instead of diverging at an angle, are closed one over the other like the blades 

 of a pair of scissors. With the exception of the largest species of Glosrina, 

 these flies are all of small or moderate size ; and even the largest Tsetse-flies 

 do not exceed 12 mm. (about half an inch) in length, exclusive of proboscis 

 and closed wings. The length of an average specimen of Lyperosia is from 3 

 to 4 mm., that of a similar specimen of Stomoxys about 6£ mm. The coloration 

 of the flies of this group is some shade of grey, brown, or yellowish brown, 

 sometimes with darker markings ; in certain of the species of Tsetse-flies, 

 although not in all, the abdomen is conspicuously banded. The wings of 

 blood-sucking Muscidre are uniformly hyaline or brownish, never blotched or 

 mottled. The sexes are usually very similar, but can generally be distin- 



" A species of Stomoxys \_S. nigra, Macq.], abundant in Maur tius during the hot season, 

 has recently been announced to be the " alirost certain " disseminator of Surra in that 

 i sland. See Lieut.-Col. Mander's " Journal of tbe Eoyal Army Medical Corps," Nov. 1905, 

 pp. 623—6. 



