144 DIPTERA OF MINNESOTA. 



account of certain disease-introducing relations to man, this family 

 is of peculiar interest, not only to the entomologist, but to all per- 

 sons interested in hygienic living. Some one quite truly said, short- 

 ly after the Spanish war, "We lost only two hundred and fifty men 

 by bullets, but five thousand by the agency of house flies," refer- 

 ring to the typhoid epidemic in some of the southern camps directly 

 traceable to the actions of house flies, and so reported by the com- 

 mission sent to investigate. This commission found that house 

 flies, after frequenting the open trenches of filth accumulating at the 

 hospitals, flew directly to the mess tables of the soldiers. 



In this family occur the Blue Bottles and "Green Bottles," the 

 Horn Fly, House Fly, Stable Fly, Screw Worm Fly, and others 

 which either cause annoyance to man, and sometimes disease, in the 

 house and elsewhere, or afl:'ect stock seriously. In our Civil War 

 the sufferings of wounded soldiers in the field, by having their 

 wounds "blown" by flies are said to have been greatly increased. 

 In South Africa the Tsetse Fly (pronounced setse), Glossina morsitans 

 (see Fig. 5) a close cousin of the stable fly, is the carrier of an or- 

 ganism which, when in the blood of certain animals, produces Na- 

 gana, or the "fly disease." 



There is another side to the shield, for some members of this 

 family are useful in the early stages of their existence. The rapid- 

 ly multiplying blow flies remove carrion which might otherwise 

 offend our nostrils ; the dung feeding species help to remove this 

 from pastures and elsewhere, and the larvae of at least one species 

 are useful in eating the eggs of locusts. 



Formerly this family contained a large number of groups of some- 

 what diversified flies, which groups are now separate families, some 

 thirty-five or more. We prefer to discuss the Muscidce in its more 

 modern, restricted sense, taking up the other families, i. e., the Bot 

 Flies, Flesh Flies. Tachina Flies, Anthomyids and others which 

 used to be included in the Muscids, in their proper places. 



All true Muscids unite in certain well defined characters. They 

 are short flies, either bare or only slightly hairy, the bristle (arista) 

 on each antenna is usually plumose, or feathery, and the first pos- 

 terior cell of the wing (Comstock's III 5) is either distictly nar- 

 rowed or closed ; the abdomen is not bristly, except occasionally 

 at the tip ; the winglcts "alulae," at base of wings are always of good 



