330 KANSAS UNIVERSITY SCIENCE BULLETIN. 



merits it appears to be a matter of stirring them to that ac- 

 tivity by the proper temperature during their life cycle. At no 

 time have I been able to find eggs deposited on the rocks under- 

 neath the traps w^here the flies emerged that did the biting. 

 Literature on the subject of their habits of biting refers to 

 them as being the worst to bite in early spring and late fall, in 

 the early morning and on cold rainy days. The argument in 

 the U. S. Department of Agriculture Year Book, 1886, quoted 

 in bulletin 5, 1896, is that SimuUmn flies oviposit before going 

 out in swarms to seek warm-blooded animals, that when once 

 gorged with blood they soon die, and that microscopical ex- 

 aminations have failed to reveal any eggs in the ovaries com- 

 posing these swarms, therefore they evidently oviposit before 

 biting. 



Our experiments brought out the fact that Simulium will 

 bite in captivity and in houses, also that they can be shipped 

 long distances and kept alive for two and three days without 

 feeding. As for keeping Simulium alive in captivity, the males 

 died soonest, living one to two days, while the females would 

 live two to four days. When filled with blood (human) we 

 kept one female alive seven and one-half days, from Friday 

 afternoon of one week until Friday morning of the followin;? 

 week, at which time the fly was destroyed in our experiments. 

 Just how long they can be kept alive by refeeding I do not 

 know. They are said to feed on maggots and caterpillars. 

 (British Diptera, p. 165.) 



It is interesting to watch the flies oviposit on the stones in 

 ripples. The female selects a stone in the ripple where a film 

 of water seeps upon the lower downstream side in very small 

 vibratory waves. In these tiny waves she places the tip of her 

 abdomen and wings and deposits from 200 to 300 eggs strung 

 back and forth as she moves along, in rows close together so 

 as to form a mass, usually from one-fourth to three-eighths of 

 an inch long and from one-sixteenth to one-eighth of an inch 

 wide. Here the waves constantly wash the tip of the abdomen 

 and afterwards keep the egg mass moist. From five to ten 

 minutes is spent in the process. In midstream, where the cur- 

 rent made the small waves best, several egg masses were piled 

 upon one another and alongside adjoining, sometimes covering 

 the whole downstream side of the rocks. Frequently a fly 

 would cease ovipositing and go away to finish on another rock 

 or perhaps to return to finish on the same rock. 



