INTRODUCTION. 103 



to try the lamp, he must make up his mind to expe- 

 rience more of unfavourable evenings than favour- 

 able* There is, however, this advantage in my 

 sedentary plan of mothing, that it can be combined 

 with reading or writing ; and the intervals between 

 the arrivals need not be lost 



" Moths are extremely sensible of any keenness in 

 the air ; a north or east wind is very likely to keep 

 them from venturing abroad. Different species 

 have different hours of flight. Thus, on a, mild and 

 dark November evening, Pcecilocampa populi will 

 occupy from seven to ten o'clock, after which it will 

 make way for Petasia cassinea, which will fly till 

 one or two in the morning, I have, for experi- 

 ment's sake, sat up in the summer till three o'clock, 

 when the whole heaven was bright with the rising 

 sun, and moths of various kinds have never ceased 

 arriving in succession till that time. Some of them 

 must come from a considerable distance. Scoto- 

 phila porpkyrea, being a heath moth, must come 

 nearly a mile. 



" Moths, like butterflies, have their peculiar 

 modes of flight, by which I can generally distin- 

 guish them on their entrance, before I can see their 

 colours. Some announce themselves by a loud 

 knock on the floor ; this is the case with Leiocampa 

 dictcea. Some ascend instantly to the ceiling, as 

 Agrotis cortlcea. Many, I might say the majority, 

 pass the lamp rapidly ; and this shows the compara- 

 tive inutility of using the lamp out of doors, where 

 only those that loiter about it can be taken. Some 



