332 MEDICAL ENTOMOLOGY 



attention ; they are dealt with fully further on. Several species of 

 MorelUa occasionally come into houses ; they can be recognized by 

 their dark bluish colour and by the two broad dark bands on the thorax. 

 Their larvae are very characteristic ; they are short and have a disc-like 

 posterior extremity on which are situated the posterior stigmata. In 

 North America, MorelUa micans, Macq., breeds almost entirely in human 

 excrement. In Madras, MorelUa hortensia, Stein, breeds in cow dung ; 

 its eggs are laid singly, and have a short curved spine. The imagines are 

 often seen on cattle, sucking up the juices which exude from wounds and 

 bites inflicted by biting flies. It is interesting to note that this species 

 and another from Kodaikanal, South India, have somewhat strongly 

 developed prestomal teeth. 



Musclna stabulans, a common stable fly, is found throughout Europe and 

 North America ; it breeds in dung, and in decaying animal and vegetable 

 matter. The species of Pyrellia and Pseudopyrellia usually breed in 

 cow dung, though some of the former oviposit in the bodies of animals. 



GENUS MUSCA, L. 



Small or moderately large insects of a greyish to dull black colour, 

 but never metallic. The eyes in the male are contiguous or nearly so, 

 the f rons being about one-fifth tJie total width of the head ; in the 

 female they are widely separated, the frons being about one-third the total 

 width of the head. The palpi are cylindrical, and slightly narrowed 

 towards their bases. The proboscis is retractile and can be tucked away 

 under the head, the usual position when the fly is not feeding. The 

 thorax is nearly always marked with four narrow to broad longitudinal 

 stripes though sometimes there are only two. Thoracic chaetotaxy 

 (macrochaetae) as follows : Humeral, 3; post -humeral, I ; notopleural, 2 ; 

 presutural, 1 ; supra-alar, I ; intra-alar, I ; post-alar, 3 ; dorsocentral, 6 

 to 8, two to three in front of the suture and three to four behind it ; 

 acrostichal- 1 to 3 ; mesopleural 6, the distance between the first and 

 second being much greater than that between any other two; the first 

 bristle is nearly always bent upwards ; sternopleural bristles 3, arranged 

 1 : 2 ; pteropleural bristles wanting. Wings hyaline, yellowish at the 

 border; fourth posterior vein bending up at a sharp angle, and first 

 posterior cell almost closed. Reproduction nearly always oviparous, but 

 may be larviparous. Larva cylindrical, posterior stigmata large and 

 widely separated, stigmal slits narrow and coiled ; puparium yellowish 

 white or olive grey to mahogany brown. 



