104 H. C. EFFLATOUN. 



black band on the lower margin is much deeper and occupies the 

 two-thirds of the segment, so that the yellow markings on the upper 

 part of the segment are isolated and much smaller. 



Length from 7 to 8^ mm. 



Becker in his excellent work on the Egyptian Diptera seems to 

 have overlooked two of the most important specific characters, 

 which are: — the presence of the vena spuria, and the absence of 

 the tufts of erect bristles on the lamellae of the male genitalia. 

 This presence or absence of the vena spuria is a very easy and 

 reliable means of distinguishing between our two Egyptian species, 

 a character which had previously been overlooked by Loew in his 

 original description of S. spinigera, and pointed out for the first 

 time by Thomson, and later by Bezzi. Another very reliable 

 and equally important character is the presence or absence of the 

 thick strong spine near the base of the posterior tibiae, below ; 

 this character is not empnasised by Becker, probably for the reason 

 that he used the common European S. pipi&ns (which also does not 

 possess the spine), for comparison with his new S. subtilis. 



This species is not uncommon in Egypt. Out of a series of fifty 

 Syritta, only six turned out to be subtilis and the rest spinigera, 

 and the six specimens (two males and four females) were all caught 

 in my garden at Shoubrah, in the months of November, December 

 and January. Becker has found it at Luxor and Suez. 



So far this species has only been recorded from Egypt but 

 very probably it exists in other parts of North Africa. 



While this work was in the press I have obtained large series 

 of the above species at Bamleh (Alexandria) (18.6.22); they were 

 hovering on Polygonum equisetifolium on the edge of a Banana 

 plantation. S. spinigera was also present, but the above species 

 greatly outnumbered it. 



