STABLE-FLIES 505 



the frequent statement that houseflies sometimes bite. They 

 differ, however, in several ways. The stable-fly is more robust, 

 browner in color, rests with the wings spread at a broader angle, 

 and has a narrow, pointed shining-black proboscis (Fig. 240) 

 which is quite different from the blunt fleshy proboscis of the 

 housefly. 



The mouthparts (Fig. 240) differ from those of many other 

 biting flies in that the lower lip, which usually merely forms a 

 sheath for the piercing mouthparts, 

 is itself a piercing organ. It is bent 

 at nearly right angles under the head 

 so that it projects straight forward, 

 being, therefore, fixed to the head 

 hke a bayonet to a rifle. The short 

 basal segment is movable and mus- 

 cular, and is used to manipulate the 

 proboscis itself. The latter has at ^^Thyp 

 its tip rasplike spines which aid in '<abel. ^P- 



perforating the skin of the host. .,^:^^'^^r::^^ 



Inside the groove in the lower lip is '^^^- antenna; ar., arista of an- 



the labrum and hypopharynx which '^Z^^iZl^Z^:^::^^ 

 together form a sucking tube. The i"™: max. p., maxillary palpus. 

 maxillary palpi, which form enclosing ^'^ erms.) 

 sheaths for the proboscis in tsetse flies, are less than half the 

 length of the proboscis in Stomoxys. 



The stable-fly is commonly believed to breed in manure, and 

 gains its name from the frequency with which it is found about 

 stables, presumably having been bred in manure. As a matter 

 of fact, the presence of stable-flies about stables is due to the 

 presence there of animals — horses, cattle, etc., — • on which they 

 feed. The breeding place which is most preferred is moist, 

 decaying straw or rotting vegetable matter. According to Herms, 

 the very best breeding places are afforded by the left-over hay, 

 alfalfa or grain in the bottoms of, or underneath, out-of-door 

 feed troughs in connection with dairies. In this soggy, fermented 

 material practically pure cultures of Stomoxys larvae may be ob- 

 tained. 



The eggs of Stomoxys (Fig. 241) are banana-shaped white 

 objects about one mm. in length, curved on one side and flat 

 on the other, with a groove on the flat side. They are de- 



