INDIAN TEYPANEIDS (FEUIT-FLIES) IN THE COLLECTION 

 OF THE INDIAN MUSEUM, CALCUTTA. 



By Prof. M. Bezzi, Turin, Italy. 

 (Plates viii-x). 



INTRODUCTION. 



Through the kindness of Dr. Annandale of the Indian Museum, I have received 

 for study a large collection of Indian acalyptrate Muscids with variegated wings, 

 most of which are Trypaneids, but a few belong to other families. In the present 

 paper I will deal with the Trypaneids, and I will reserve the rest for another paper, 

 which will embrace the Heleomyzids, I^auxamids, Ortalids, Ephydrids and Droso- 

 philids. 



I will make the present paper the more extensive inasmuch as the Oriental and 

 AustraUan Trypaneids are little known and in most cases are as yet in great confu- 

 sion. This is perhaps due to the fact that the great monographer of the Trypaneids, 

 Prof. Loew, was very little acquainted with Oriental forms ; though a great portion 

 of Palaearctic, Nearctic, Neotropical and even Ethiopian species were named and des- 

 cribed by him^, in the Oriental or Australian fauna he has not described even a 

 single species! Most of the species are due to Mr. Walker, who, with his well-known 

 inaccuracy, has mixed up the matter in a very disagreeable manner. 



The family of the Trypaneids, however, is of very great economic importance, 

 because it contains a great many harmful insects which are generally known as 

 ' ' Fruit-flies. ' ' 



2. DISTINCTIONS OF THE FAMII^Y AND GENERAL CHARACTERS. 

 Among the so-called acalyptrate Muscids, the family of the Trypaneids is a 

 natural one and not difficult to recognize; as however in the Oriental fauna there 

 are many related forms with a very similar wing-pattern, which may easily be con- 

 founded with them, I think it better to give here the essential characters of the 

 family. These are : — 



1. The frons bears a row of bristles in the anterior part of its lateral 



borders, the so-called lower fronto-orbital bristles. Post- vertical bristles 

 parallel or divergent, never crossed. There are no distinct vibrissae. 



2. The thorax with a characteristic chaetotaxy on both dorsal and lateral 



surfaces, consisting . of strong bristles which only in a few cases are 



1 Prof. Loew has named 32% of the Palaearctic, 28% of the Ethiopian, and 21% of the Nearctic 

 species. 



