340 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Now Simuliiim flies are stuborn creatures to handle, for the 

 reason that frequently they seem unaffected by light stimuli, 

 at least will remain in a darkened chamber instead of coming 

 into the lighter one. It frequently took an hour to get a few 

 flies to go from a cone in a trap, darkened by covering it with 

 a double thickness of black cloth, into a lighter chamber. The 

 flies were more active and much more easily handled in the 

 early morning while it was cool than later in the day after 

 the temperature had risen. The heat of the day seemed to 

 make them sluggish and inactive, so much so that it was ex- 

 tremely difficult to induce them to go from one cage to another 

 at midday. Again in the evening, when the heat of the day 

 had subsided, they became more active. Literature refers to 

 them as being a cool-weather fly, as most offensive with their 

 biting in the early morning and on cool days. Other places 

 they are spoken of as not biting in warm weather during the 

 summer. 



When Simidium flies move they generally go very quickly 

 and fly with a great deal of force. At first we removed them 

 from a trap into a glass bottle, but they flew against the 

 transparent sides of the bottle with such force that it seemed 

 to stun them. Their antennse are comparatively large and 

 protrude forward, so that, in flying against the glass, their 

 antennse, which are probably their sense organs of touch and 

 perhaps of sound and smell, received a shock that seemed to 

 make the flies more stupid. We then tried taking them into a 

 gauntlet-shaped wire cage covered with cheese cloth. In this 

 they had more room and softer walls to butt their antennse 

 against. Here they were more quiet and more easily handled. 



Plate XXXVIII, figure 3, shows the method of taking them 

 out of a trap into a bottle, except that we placed a black cloth 

 around the cone to darken it at that time. We substituted 

 the gauntlet cage for the bottle. In this manner, when the 

 pupse were numerous, we were enabled to secure plenty of 

 flies for our experiments. 



ECONOMIC IMPORTANCE OF SIMULIUM. 

 Considerable literature has been written on the depredations 

 of "black flies," "buffalo gnats," "turkey gnats," and "sand 

 flies" (Simulium) since the latter part of the eighteenth cen- 

 tury, in Europe, and since the pioneer days of settlement in 

 the Mississippi river valley of America. Theobold (British 



