emery: SIMULIUM VITTATUM in KANSAS. 325 



As a rule, in regions where S. vittatum occurs the larvae 

 are found in the ripples and falls of creeks and small streams, 

 not rivers, that flow the year round. The most essential con- 

 dition for the well-being of these aquatic creatures is rapid 

 motion of the water in which they live. Not only did the 

 writer find this to be the condition, but in the Kansas Bio- 

 logical Survey notes for 1912, Mr. E. C. O'Roke writes, at 

 Hays City: "While scouting about for a camping place we 

 observed larvae and pupse of sand flies on a concrete dam and 

 on the rocks below it in Big creek." In another part of the 

 notes Mr. A. E. Mallory, at Rush Center, says : "We found 

 many Simuliiim larva? and pupje in the ripples." In the same 

 field notes Mr. F. X. Williams, at Ness City, writes: "In a 

 small branch of Walnut creek, where the ripples are weak and 

 the bottom is pebbly, but with no stones, I found Simulium 

 larvae, pupse and eggs plentiful on the sedges lying flat in the 

 ripple." This last note shows that while there were no stones 

 to break the flow of the water, yet the sedges, on which the 

 Simulium lived, were washed by the current. 



As to the character of the water in their breeding places, it 

 is generally clear and well aerated, though sometimes it con- 

 tains considerable organic matter. Two of the breeding 

 places observed in Kansas where the flies were very numerous 

 were streams that carried sewage. One was at Rosedale, 

 Kan., a suburb of Kansas City, and the other was at Oswego, 

 Kan. Doctor Forbes, of Illinois University, states, in his 

 report on SimnUnm of that state, that the larvae were found 

 in the sewage drains far up into the city of Chicago. 



Since their habitat is in ripples or in places where the water 

 is accelerated by an obstruction, it is interesting to observe 

 what takes place in standing water. Our observations in the 

 laboratory showed that they died in about an hour; at least 

 they would not respond to stimulation after that time in a 

 vessel of water. Consequently, in a stream when the larvae 

 are swept into quietly running water, they drown unless they 

 can maintain themselves in the current long enough to float 

 to another ripple. In a little stream near Oswego, in which 

 there were two ripples about fifty yards apart, the second 

 ripple or the one below was narrowed so I could observe ap- 

 proximately the number of larvte on the stones. After dis- 

 turbing about fifty or more larvae in the upstream ripple, 



3-Univ. Sci. Bull.. Vol. VHI. No. 9. 



