viii, B, 1 Mitzmain: Stomoxys calcitrans Linnxus 43 



that they become easy victims of spiders, and the cautious 

 observer, after a little practice, may easily capture the fly with 

 the thumb and forefinger. This method of collecting leaves the 

 fingers stained with considerable blood from the engorged 

 parasite. Feeding is usually resumed when the heat of the day 

 has subsided, and after the second daily engorgement another 

 long rest follows. 



The occurrence of Stomoxys under natural surroundings has 

 been carefully noted. The following observations will throw 

 some light on the habits of this fly. 



On April 3 at 5 a. m. (in bright moonlight) the cattle shed 

 and the stock in the open woods near the laboratory were in- 

 spected. At this time there was not an indication of a fly. A 

 few mosquitoes buzzed about, but not enough to cause any ap- 

 preciable stir among the resting animals. I waited in the woods 

 with the resting cattle and carabaos until 5.20 a. m., when a 

 remarkable awakening took place. Every animal, almost simul- 

 taneously, was on its feet switching its tail and squirming. A 

 small band of flies had made their appearance, and at 5.30 a. m. 

 the flies had attacked the cattle and carabaos in swarms. Dense 

 black patches of them were seen on white cattle. The same 

 phenomenon was noted at the shed quartering the work animals. 

 Flies which at 5.15 a. m. were found resting on the boards 

 of mangers and stalls were actively infesting the awakening 

 cattle at 5.30 a. m. This invasion continued until sunrise at 

 6.40 a. m. when the hordes of flies gradually diminished. At 

 this time of the year the greatest infestation from these flies is 

 the hour preceding 6.30 a. m. Flies of this species were attack- 

 ing stock in the sheds at 6 a. m., even as late in the year as 

 October 24. The animals were terrorized by the quick sharp 

 pricks of the stinging flies, and seemed unusually restless, moving 

 both laterally and backward and forward to escape attack. Some 

 actually reared into the feed mangers. At this time of the day 

 it was very dark and sultry. 



LONGEVITY 



An attempt was made to determine the longevity of this 

 species, both with flies collected in their natural state and flies 

 bred in the laboratory. In either case only an approximation 

 is obtained, since artificial conditions were present, which might 

 have increased or diminished the natural length of life. 



Guinea pigs and monkeys were utilized to provide food for 

 the flies which were kept separately in suitable glass tubes. 

 When not being fed, the flies were kept in the dark at a tem- 



