ROLE OF STOMOXYS CALCITRANS. 513 



found the most convenient. A piece of white filter paper con- 

 forming to the size of the tube was found ideal to regulate the 

 moisture requirements, and this was changed at least every two 

 or three days. It was found advantageous to change the tube 

 not oftener than twice each week. In feeding it was not found 

 necessary to screen the mouth of the tube. The base of the tube 

 was directed toward the window light and the filter paper 

 removed; the tube was then inverted immediately over the 

 animal's body. The fly after feeding was induced to release its 

 hold on the skin of its host by gently tapping the tube, and 

 gradually inclining it toward the light, after which the filter 

 paper was restored and the tube closed with a cotton plug. 



The flies when not feeding were kept in the dark at a tempera- 

 ture between 20° to 26° C. 



Martini < 32) kept experimental flies, Stomoxys calcitrans, at a temperature 

 of 23° C. The longevity is not stated. 



METHODS OF APPLYING THE FLIES TO THE HOST. 



Monkeys. — In applying large numbers of flies in a bottle, the 

 following method was pursued. First the monkey was strapped, 

 abdomen down, to an improvised stock by means of surgical 

 gauze or twine, securing the wrists and ankles which were 

 bandaged previously to prevent chafing. Then the tail was 

 closely cropped, bound to a stout wire with straps of gauze, 

 and thrust into a narrow-necked bottle which harbored the 

 flies to be fed. The other end of the wire was kept at a 

 convenient distance from the mouth of the bottle to facilitate 

 manipulation. Wiring the tail was resorted to on account of 

 the animal switching the appendage against the glass and crush- 

 ing numerous flies. 



Another method was employed with flies fed individually from 

 tubes inverted over the thigh or other convenient portions of 

 the monkey, held in a similar position on the stock. At least two 

 flies could be fed at once in this manner. (Plate IV.) 



Guhiea pigs. — ^When a guinea pig was subjected to fly bites 

 in a large museum jar it was found to be of advantage to im- 

 mobilize it by strapping to a frame of brass wire. (Plate II.) 

 This was done in order that movements of the animal would 

 not interfere with taking the fly census during feeding, and to 

 prevent the guinea pigs from eating the flies. Cropping the 

 hair of this host was found to assist the parasites in feeding. 



In the use of a museum jar it was necessary to hold it horizon- 

 tally with the bottom toward the light. Here the majority of 



