North American Diitkra. ru 



M U S C I 1) .!<:. 



The very large family of Muscidiu has been divUleil into miinerous 

 subdivisions, wiiich by some entomologists are accredited with fam- 

 ily rank. The number and limits of these sub-families, are more or 

 less the subjects of diverse opinion by dipterologists. The follow- 

 ing characters will apply to the family in its entirety : Antenna; 

 three jointed, the third joint simple, usually round or oval, with dor- 

 sal arista. Proboscis always present, usually short, with dilated 

 labella, sometimes elongate and adapted for piercing. Auxiliary 

 vein sometimes entirely wanting, sometimes coalescent with the 

 first longitudinal vein ; one submarginal, three posterior cells 

 present ; basal cells small, the second sometimes coalescent with the 

 discal, the latter sometimes absent; pulvilli present ; empodia never 

 developed pulvilliform. 



The flies are often small, or minute, usually more or less bristly, 

 and not often much pilose. The larvaj are very variable in their 

 habits ; pupie always enclosed in the larval skin. 



Two chief divisions are recognized, based upon the size of the teg- 

 ulaj, the Muscidae caly ptra ta; and aca ly p tr a ta;. In the 

 former they are well developed, in the latter small or rudimentary. 

 All the families of the former (except the An thorny Ida;) have 

 the first posterior cell either closed or narrowly open, a character 

 rarely found in the second division. 



The differential characters of the calyptrata; liave already been 

 given. Tlie flies have hitherto received but little study in this 

 country and it is at present impossible to give a table of the genera 

 that would be of much value. 



For the M u s c i d a; a c a 1 y j) t r a t a> I am prepared to give only a 

 translation, with some modifications, of Scliiner's table of subfami- 

 lies (Fauna Austriaca), with a reproduction of the characters given 

 by Loew in his Monographs. 



MUSCID^v ACALVrrUAT^C. 

 1. Auxiliary vein present, distinctly separated from the first longi- 

 tudinal vein, terminating separately in the costa ; the first 

 longitudinal vein usually terminiites at or beyond the middle 

 of the wing. . . ....... 2 



Auxiliary vein absent, rudimentary or incomplete ; the first lon- 

 gitudinal vein usually terminates before the middle of the 



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