MOTIONS OF INSECTS. 365 



when they return from their more distzint excursions 

 during the autumn, may with more certainty be re- 

 ferred to this cause. White says, they rendezvous 

 by thousands over Selborne Down, whcehng round 

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

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

 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 dapping 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 thn dexterity of their motion, 

 may be considered not a little remarkable, from the 

 circumstance of tiieir 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 ;t unless it may be that the drops glide off 

 their wings as they do otl'thc feathers of a duck, whde 

 the elasticity of their bodies may save them from ac- 

 cidents, even wlien they chance to be pelted. 



A very pretty species of these choral flies ( Chiro- 

 nomus atcrrimiis Meigex), is exceedingly common 

 in the vicinity of London, appearkig 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 tiic male has his 

 antennae adorned with beautiful lead-gray plumelets. 

 Though groups of these 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 {Culex pipiens), they can brave the bleak winds 

 of winter, — yet they often crowd into our a|)artments, 

 like many others of the family. We have just been 



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

 VOL. VI. 31* 



