272 OBSERVATIONS ON INSECTS. 



had been shewn to Mr. Newman, the editor of the 

 Zoologist, who pronounced them to be the Chiro- 

 nomus prasinus.* 



Broods of a small jet-black species of Chirono- 

 may sometimes be observed in winter actu- 

 ally hovering over snow. From the freedom with 

 which black surfaces radiate out caloric, one would 

 think the colour of these insects must have the 

 effect of reducing the temperature of their bodies, 

 even below that of the air. Yet they seem almost 

 as active, and as much at their ease, as if it were 

 summer. 



TRICHOCERA HIEMALIS. 



THE power which some of the Tipulidcs have of 

 resisting cold is very remarkable. During the severe 

 winter of 1829-30, in the month of January, when 

 the mean temperature of the twenty-four hours was 

 varying from 28 to S3 J, and in two instances de- 

 scended as low as 25 and 16 respectively, a brood 

 of the Trichocerahiemalis,M.eig., suddenly made their 

 appearance in considerable numbers, settling upon 

 the walls of different outbuildings, as if they had 

 just emerged from the pupa state ; and though 

 they did not offer to take wing for several weeks, 



* See a notice of similar clouds of dipterous insects being ob- 

 served in Ireland, in Ann. and Mag. of Nat. Hist. vol. x. p. 6. 



f Either the C. byssinus of Meigen, or some closely allied spe- 

 cies. 



