Februaiy, '13] HUNTER: PELLAGRA AND SAND-FLY 97 



1. The survey on the distribution of sand-flies in Kansas. 



2. A detailed investigation into their hfe habits and conditions 

 under which they exist. 



3. Continuation of the inoculation experiments. 



Since these investigations when completed will be pubHshed in 

 full it is not the purpose of this paper to occupy your time now with 

 details, but rather to give in briefest possible form a summary of the 

 work thus far, under the above heads. 



I — Distributon: The only species thus far found to be generally 

 distributed over the state is Simulium vittatum. The survey thus far 

 seems to show that the immature forms of this species may be found 

 where ever there is trickhng water, throughout the summer months. 

 I use the word trickling in order to include waters which flow from 

 running springs, in little rivulets through the grass. Here attached 

 to the blades of such grass Simulium larvae sometimes abound. 



II — Life History: This species is not confined to clear or pure 

 water. A short distance below where the septic tank of a city of the 

 second class empties into the Neosho, larvae and pupae were abundant 

 this season. 



In an examination of the riffles for a considerable distance along 

 the bed of a small creek, the only "place these larvae were found was 

 in the riffles running through a hog lot. There the hogs were wallow- 

 ing and polluting the waters in and above the riffles. 



They are not confined to the rural districts but are found in Turkey 

 Creek which runs through a populous part of Kansas City. Last 

 season they were more abundant here than elsewhere. 



The females prefer to oviposit in the evening and place their eggs 

 on wet leaves in shallow ripples or on rocks in the same position. 

 They usually place the tip of the abdomen in the water where the 

 water comes up on the rocks in a thin film on the down side of the 

 stream. As the fly oviposits she moves along, stringing the eggs, 

 but holding on to the rock above the water while the tip of the wings 

 and abdomen are vibrating in the water. This process occupies in 

 all about ten minutes and about 200 eggs are usually deposited. 



When first deposited the eggs are whitish or creamy in color, turning 

 yellowish, then brownish and almost black at the time of hatching. 



When first hatched the larvae are almost invisible with an ordinary 

 12x lens. 



The duration of the egg stage depends somewhat upon the temper- 

 ature of the surrounding water, though usually lasting about a week. 



The length of the larval stage depends upon the temperature of 

 the water and upon its rapidity. It varies from three or four weeks 



