MOTIONS OF INSECTS, 365 



when they return from their more distant excursions 

 during the autumn, may with more certainty be re- 

 ferred to this cause. White says, they rendezvous 

 by thousands over Selborne Down, wheehng round 

 and diving in a playful manner in tlie air, and when 

 this ceremony is over, with the last gleam of hght, 

 they retire to the deep beech woods of Tisted and 

 Kepley, It may not be improper, however, to dis- 

 tinguish between this and the restless tossing about 

 and flapping of the wings, often exhibited by rooks 

 previous to a storm, which more usually occurs in the 

 morning, and closely resembles the tossing of sea- 

 birds on the billows during a gale.* 



The quickness of the vision of tipulidan gnats, and 

 the rapidity as well as the dexterity of their motion, 

 may be considered not a little remarkable, from the 

 circumstance of their flying unwetted in a heavy show- 

 er of rain, whose drops — bigger than their own bo- 

 dies — if they fell upon them, must dash them to the 

 ground ; "f unless it may be that the drops glide off* 

 their wings as they do off* the feathers of a duck, while 

 the elasticity of their bodies may save them from ac- 

 cidents, even when they chance to be peked. 



A very pretty species of these choral flies ( Ckiro- 

 nomus atcrrimiis Meigen), is exceedingly common 

 in the vicinity of London, appeari-ng about the close 

 of winter, and readily distinguished by its shining 

 snow-white wings, rendered more conspicuous by the 

 contrast of its black body, while the male has his 

 antennse adorned with beautiful lead-gray plumelets. 

 Though groups of tliese may be found sporting on 

 the borders of woods and near water, even in January, 

 proving that, though not half the size of the common 

 gnat {Cidex pipiens), they can brave the bleak winds 

 of winter, — yet they often crowd into our apartments, 

 like many others of the family. We have just been 



* J. R. t Kirby and Speuce, vol. ii, p. 374. 

 VOL. VI. 31* 



