112 DIPTERA. 



They form a small group, and several of the species are 

 rare. Conops rufipes and C, quadrifasciata are generally 

 distributed and common ; the former has the second 

 abdominal segment very attenuated, the posterior end 

 thick ; the abdomen of the other species is not very 

 thin at the base. The flies of this family are prettily 

 coloured, but not most gracefully formed. 



The Muscidw are, of all the various families of 

 Diptera, the most remarkable, " on account of their 

 very numerous groups, species, and individuals, of their 

 extensive variation of structure, and of their great im- 

 portance in the economy of nature ; some species are 

 insectivorous, many are parasitic in the larva state, the 

 rest feed on living or decaying animal or vegetable 

 matter" (Walker's Diptera). The species are divided 

 into two groups : — 



(1). Calypterse, in which the alulae or winglets are 

 distinct. 



(2). Acalypterse, in which they are indistinct or 

 absent. 



The former are distinguished by their comparatively 

 large size, compact, dark, or metallic bodies, and fre- 

 quently by the development of the fourth and fifth 

 joints of the antennae or the basal joints of the arista. 

 The insects of the latter group are comparatively small, 

 with bodies less compact ; their flight is more feeble, 

 and the antennae are less developed. Mr. Staveley 

 remarks that in the habits of both larva and fly in the 

 several groups of genera in this one family, there is 

 nearly as much variety as in all the other families of 

 Brachyc^ra together. Thus while among the flies are 

 found flower-lovers feeding on honey, blood-suckers. 



