DIPTERA. 453 



The adult fly, on emerging from the pupa-skin, rises to 

 the surface of the water and takes flight at once. Soon 

 after this, the eggs are laid. We have often watched the 

 flies hovering over the brink of a fall where there was a thin 

 sheet of swiftly-flowing water, and have seen them dart into 

 the water and out again. At such times we have always 

 found the surface of the rock more or less thickly coated 

 with eggs, and have no doubt that an ^g^ is fastened to the 

 rock each time a fly darts into the water. 



The above account is based on observations made on the 

 Innoxious Black-fly, Sifnuliuni innoxiuin (Si-mu'li-um in- 

 nox'i-um), which is exceedingly common in the streams 

 about Ithaca, N. Y. This species, fortunately, is not blood- 

 thirsty, for, notwithstanding its great abundance in this 

 locality, we have never known it to bite. 



The Southern Buffalo-gnat, Simulium pecitarum (S. pec- 

 u-a'rum), of the Mississippi Valley is a terrible pest, which 

 causes the death of many mules and other domestic animals. 

 The popular name of this insect refers to a fancied resem- 

 blance in the shape of the insect when viewed from one side 

 to that of a buffalo. 



The Turkey-gnat, Simulium meridionale (S. me-rid-i-o- 

 na'le), closely resembles the preceding in habits, infesting 

 all kinds of domestic animals ; but as it appears at the time 

 that turkeys are setting and causes great injury to this fowl, 

 it is commonly known as the Turkey-gnat. 



The Adirondack Black-fly, Simidium molestiim (S. mo- 

 les'tum), is a scourge in the mountains of the Northeastern 

 States. 



Family Tabanid^ (Ta-ban'i-dae). 



The Horse-flies. 



The horse-flies are well-known pests of stock, and are 

 often extremely annoying to man. They appear in sum- 

 mer, are common in woods, and are most abundant in the 

 hottest weather. 



