.1 Monograph <>/ Egyptian Diptera. 77 



contracted. At the hind margin of the prothoracal segment lie tlie 

 anterior spiracles; they form short, brownish, a little curved 

 horns, but they may be quite retracted and then only seen as points. 

 Above, on the first abdominal segment two somewhat circular 

 spots are seen: these are the points through which the anterior 

 spiracular tubes in the pupa protrude. 



The anus lies below in front of the tail; protruding from its 

 opening is sometimes seen a bundle of thread-like appendices, the 

 use of which is not known; Trybom takes them to be an organ of 

 locomotion, perhaps also of respiration. The larva is of a greyish 

 or yellowish-white colour and about 18 mm. in length excluding 

 the tail. The pupa is brownish, its upper anterior end forms a 

 flattened declivity, at the hinder border of which the anterior 

 spiracular tubes protrude; these tubes are long, reaching 3 mm., a 

 little curved, directed upwards and forwards and a little diverging; 

 on the lower side they are beset with small tubercles (in other spe- 

 cies such as tenax these tubercles lie on the sides and above, but 

 not below); at the front margin of the pupa the anterior larval 

 spiracles are seen as two short horns, the pupa has thus in all four 

 horns, two long ones above and two short ones below them. The 

 larval tail is still found in the pupa, curved in various ways, and 

 (in the ventral side, the prologs are visible. The length is about 

 12 mm. 



No distinguishing characters ate known for the different 

 species, but according to Miall such may be found in the small 

 spinules on the dermis; these being in some species simple, in 

 others branched in various ways. For pupating the larva quits the 

 water and pupates in the vicinity, generally on the earth but they 

 are also sometimes seen at the surface of the water or they may 

 suspend themselves on stalks, palings etc. by the tail. The eggs 

 are deposited a little above the surface of the water. The eggs are 

 whitish, oblong and finely shagreened. 



The species of Eristalis are handsome, conspicuous flies and 

 fairly good hoverers ; they occur generally on flowers especially on 

 Composita?, UmbelliferEe and Cruciferae in gardens as well as in 

 waste places, and in valleys; I have even found E. quinquelineu- 

 tus hovering over a bush of Zygophyllum coccineum in the desert 

 more than one hundred miles away from any cultivation. They also 

 frequently occur near water. 



Of the genus more than 45 species have been recorded from 

 the Palaearctic region and of these hitherto only 4 have been found 

 in Egypt. 



