TOBPIDITT OF SWALLOWS. 227 



taininent, and information, at the same time ; and would 

 open a large and new field in natural history. "Worms work 

 most in the spring, but by no means lie torpid in the dead 

 months ; are out every mild night in the winter, as any per- 

 son may be convinced that will take the pains to examine 

 his grass plots with a candle ; are hermaphrodites, and much 

 addicted to venery, and consequently very prolific. 



LETTEE LXXVIIL 



TO THE SAME. 



SELBORNE, Nov. 22, 1777. 



DEAR SIR, You cannot but remember that the 26th and 

 27th of last March were very hot days ; so sultry, that every 

 body complained, and were restless under those sensations to 

 which they had not been reconciled by gradual approaches. 



This sudden summer-like heat was attended by many sum- 

 mer coincidences ; for, on those two days, the thermometer 

 rose to sixty-six in the shade ; many species of insects revived 

 and came forth ; some bees swarmed in this neighbourhood ; 

 the old tortoise, near Lewes, awakened, and came forth out 

 of its dormitory ; and, what is most to my present purpose, 

 many house-swallows appeared, and were very alert in many 

 places, and particularly at Cobham, in Surrey. 



But as that short warm period was succeeded as well as 

 preceded by harsh, severe weather, with frequent frosts and 

 ice, and cutting winds, the insects withdrew, the tortoise 

 retired again into the ground, and the swallows were seen 

 no more until the 10th of April, when the rigour of the 

 spring abating, a softer season began to prevail. 



Again, it appears by my journals for many years past, that 

 house-martins retire, to a bird, about the beginning of Octo- 

 ber ; so that a person not very observant of such matters 

 would conclude that they had taken their last farewell ; but 

 then it may be seen in my diaries, also, that considerable 

 flocks have discovered themselves again in the first week of 

 .November, and often on the fourth day of that month, only 



