236 Miss S. L. M. Summers on 



difficult to get a suitable basis for a table. In going over this 

 collection 1 have found that the characters most to be relied 

 on are : — (J) the widtli of the frons in relation to the width 

 of the head; (2) the width of the median line on the thorax, 

 and (3) the colour of the legs. The abdominal markings can 

 be relied on to a certain extent only. In Stonioxys caJcitrans 

 the spots on the abdomen may vary considerably, but the 

 species can be easily recognized by the broad frons, the 

 narrow stripe on the thorax, and the black legs. 



Since the determination of the species depends to a large 

 extent on the breadth of the front and of the median stripe 

 on the thorax, it is imperative to get exact measurements. I 

 find that I can get these measurements exactly by making a 

 camera lucida tracing of the head and thorax of the specimen, 

 using a two-inch lens, and tiien measuring the drawing. 

 The measurements of die front in this paj)er are taken at the 

 vertex. The colouring of the face is not constant, and there- 

 fore cannot be used as a definite character. In some species 

 the colour of the tibise may vary; e. g., in Stomo.vys nigra I 

 have found four with quite brown tibise (in the second pair 

 of legs). I'liese four agree with the type of St. nigra in 

 every other respect, and the light colour of the tibiae of the 

 second pair of legs is not sufficient to make a new species of 

 these specimens. Besides, Griinberg, in his description of 

 Stomoxys glauca, which has since been shown to be a synonym 

 of iStomoxys nigra, ]\lacq. (Austen), remarks that sometimes 

 the tibise are quite brown (Giiin. 1907, ' Die blutsaugenden 

 Dipteren '). 



In his revi.-ion of the Oriental blood-sucking ^Muscidoe 

 (Records of Ind. Mus. vol. iv. no. iv. 1910) Mr. Ijrunetti 

 gives a table of the Oriental species of Stomoxys, but I find 

 lie does not include Stomoxys nigra. 



The following table is drawn up according to the characters 

 aforementioned : — 



Talile of Oriental Species of Stoinoxys. 



A. Legs mainly black 1. 



B. Legs m.iinlv brown 2. 



L Legs luaiuly black. 



1. Front in (S wide, \ or j width of head . . 3. 

 Front in c? narrow, ^ or less widtli of head. 



Abdomen with round spots sitiois, Eoud., cJ • 



3. Dorsal stripe on thorax narrow (o-'o nun.) 



at anterior end, widening towards tlie 



posterior end. Abdomen spotted .... J. 



