99 



ON THE FRUIT-FLIES OF THE GENUS DACUS (s.l.) OCCURRING IN 

 INDIA, BURMA, AND CEYLON. 



By Prof. M. Bezzi, 

 Turin, Italy. 



As stated in my previous paper* on the Ethiopian species of Dacus, the Oriental 

 forms of this genus show much more variation in their structural and ornamental 

 features. They may be therefore divided into no less than five well defined genera, 

 only one of which is common to both faunal areas. Reserving for later publication a 

 third paper on the Oriental (and Australian) species, I will give here some notes on the 

 classification and feeding habits of the species from British India. 



Since the publication in 1913 of my paper on the Indian Trypaneids,t I have 

 received from various sources a large amount of material, which enables me to give a 

 better definition of the species and to add much information as to fruits on which 

 they feed. The material was received : — {a) from the Imperial Bureau of Entomology ; 

 (b) from the Indian Museum, Calcutta ; (c) from the Pusa Agricultural Research 

 Institute, forwarded by the Imperial Entomologist, Mr. T. B. Fletcher, who has 

 supplied the data as to the host fruits ; (d) from the Dehra Dun Forest Research 

 Institute, forwarded by Professor A. D. Imms ; (e) from Professor L. Petri of Rome, 

 material bred at Peradeniya, Ceylon, by Mr. E. E. Green ; (/) from Professor E. 

 Bugnion, of Lausanne, material collected by him in Ceylon. 



The fruit-flies which are grouped around Dacus are principally distinguished from 

 other Tr}'^aneids by their reduced chaetotaxy, as established by me and accepted by 

 Professor Hendel in his synopsis of the genera of the family. J This reduction consists 

 in the simultaneous disappearance of the following macrochaetae :■ — ocellar, post- 

 vertical, humeral, praesutural, dorso-central and sternopleural ; usually the bristles 

 of the occipital row and those on the under side of the front femora are also wanting 

 or much reduced. There are no other genera of fruit-flies in which all these bristles 

 are w^anting at the same time, except a few Oriental genera in which this is the 

 case, though they have not a Z)acM5-hke appearance. They must however be 

 associated with the true Dacinae, and they constitute another pecuUarity of the 

 Oriental fauna as compared with that of the Ethiopian region. 



The following is a table of the Oriental and AustraUan genera of Dacinae at present 

 known : — 



1 (12). Arista bare ; scutellum broader than long, rounded, convex above, not 

 carinate at the sides ; abdomen not linear, usually broader than the thorax ; wings 



*BuU. Ent. Research, vi, September, 1915, pp. 85-101, 14 figs. 



fliuliaii Trj'paneids (Fruit -flics) in the Collection of the Indian Museum, Calcutta. 

 Ilemoirs of Ike Indian Miiseam, iii, No. 3, May 1913, pp. 51-175, pi. viii-x. 



JDie Gattungen dor Bolivfliegen ; analytischo iibersiclit aller bisher bekannteu 

 Gartungcn dor Tcphritiiiao. Wicn. eniovi. Zeilung, xxxiii, April 1914, pp. 73-98. 



rC23S) Wt. P12/10D. 1,000. lO.lG. R.&F.Ltd. Gp. 11/1. 



