370 LYPEROSIA [CH. 



They are very common on domestic animals and generally 

 cluster on any small sores. They also take advantage of the 

 wounds caused by the bites of Tabanids, etc. In the Philip- 

 pines, Mitzmain has observed these insects to wait for a Tabanus 

 to finish feeding and then immediately suck up the drop of 

 blood that oozed from the open wound caused by the larger 

 insect. They are also capable of obtaining blood for themselves, 

 and the only European species, L. irritans Linn., has the 

 habit of clustering in a dense mass about the base of the horns 

 of cattle. Lyperosia rarely attacks man, but regarding a 

 Uganda species, L. punctigera, Austen records the following 

 observation by the collector (the late Dr W. A. Denshaw) : 

 " These flies were noticed in great numbers in one camp only 

 near the Nile, and were very troublesome to my boys early one 

 sunny morning ; they clustered thickly on any small sore, and 

 quickly filled themselves ; though preferring to feed in this 

 way, they seemed also to insert the proboscis into sound 

 skin." 



Life-cycle. The life-history of Lyperosia irritans Linn, has 

 been investigated in America by Riley and Howard. The eggs 

 are laid singly on the surface of freshly dropped cow-dung. 

 They are light reddish-brown in colour and vary from 1-25 to 

 i'37 mm. in length, by 0-34 to 0-41 mm. in breadth. As soon 

 as they hatch the larvae penetrate into the dung and in this 

 situation complete their development. The fully-grown larva 

 is dirty white in colour and about 7 mm. in length. The 

 posterior stigmatic plates, situated on the terminal segment, 

 are large, very dark brown, and almost circular, but with their 

 inner adjacent margins almost straight, and each has a circular 

 central opening. On the ventral surface of the anal segment 

 is a dark yellow chitinous plate bearing six irregular paired 

 tubercles, and the whole plate is surrounded by an area of 

 coarsely granulated skin. 



The pupae are found in the ground beneath the dung, at a 

 depth of about 2 cms. The puparium resembles that of 

 the house-fly, being dark brown in colour and barrel-shaped. 

 Its dimensions vary from 4 to 4-5 mm. in length, by 2 to 

 2*5 mm. in breadth. 



