ADDITIONAL NOTE 



ON THE SWARMING AND BUZZING OF HARLEQUIN-FLIES 



(See pp. 9 and 99.) 



Mr. T. H. Taylor furnishes the following observations 

 on swarms of harlequin-flies, which were received too 

 late for insertion in the proper place. The text has, 

 however, been altered in accordance with the new infor- 

 mation: — 



' When a swarm of harlequin-flies is dancing some ten 

 or fifteen feet from the ground, it is observed that at 

 intervals a pair of flies leaves the rest, and descends. If 

 the pair be captured, it will be generally found to consist 

 of a male and a female. Occasionally it consists of two 

 males. Sometimes there are three flies in a cluster ; one 

 captured triplet yielded two males and a female. After 

 a mating pair has flown a short distance from the swarm, 

 the union is broken ; the male returns to its comrades, 

 but the female flies away. The number of females in the 

 swarm is probably never large ; it seems to be affected by 

 wind. In calm weather pairing is readily accomplished, 

 and the females soon leave the swarm, but a high wind 

 renders pairing difficult, and the females remain longer 

 in the company of the males. On a calm evening a sweep 

 of the net yielded 700 flies, all of which were males. On 

 another evening, when the swarm was much disturbed 

 by wind, 4,300 flies were captured, twenty-two of which 

 were females. 



