398 C. GORDON HEWITT. 



domibus, etiam Americas. Larvae in simo equinas. Pupae 

 parallele cubantes." 



Later Fabricius described it more fully in his ' Genera 

 Insectorum/ The House-fly, together with the Blowfly, and 

 the blood-sucking flies Stomoxys and G-lossina belongs to 

 the family Muscidae, which is characterised by having the 

 terminal joint of the antenna the arista always combed or 

 plumed and by the absence of large bristles or macrochaetae 

 on the abdomen. The Muscidae, together with the Antho- 

 myidae and Tachiuidae constitute the group Muscidae 

 calypteratae are characterised by the possession of squamae, 

 small lobes at the bases of the wings which cover the halters. 

 In the acalyptrate muscids the squamae are absent or rudi- 

 mentary. These two groups belong to the suborder Cyclor- 

 r hap ha, one of the two primary divisions of the Diptera. 

 The Cyclorrhapha have coarctate pupae, the pupal case 

 being formed by the hardening of the last larval skin, and 

 the flies escaping through a circular orifice formed by the fly 

 pushing off the end of the pupa by means of an inflated sac- 

 like organ the ptilinium which is afterwards withdrawn into 

 the head, its presence being marked by a frontal crescentic 

 opening the lunule. The other sub-order the Orthorrhapha 

 have obtected pupae. 



The most complete specific description of Musca domes- 

 tica has been given by Schiner (1864), of which the follow- 

 ing is a free translation : 



" Frons of male occupying a fourth part of the breadth of 

 the head. Frontal stripe of female narrow in front, so broad 

 behind that it entirely fills up the width of the frons. The 

 dorsal region of the thorax dusty grey in colour with four 

 equally broad longitudinal stripes. Scutellum grey, with 

 black sides. The light regions of the abdomen yellowish, 

 transparent, the darkest parts at least at the base of the 

 ventral side yellow. The last segment and a dorsal line 

 blackish brown. Seen from behind and against the light the 

 whole abdomen shimmering yellow, and only on each side of 

 the dorsal line on each segment a dull transverse band. The 



