INTRODTJCTIOil. 
103 
to try the lamp, he must make up his mind to expe- 
rience more of imfavourable evenings than favour- 
able. There is, however, this advantage in my 
sedentary plan of mothing, that it can he 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, Pwcilocampa popidi will 
occupy from seven to ten o’clock, after which it will 
make way for Petasia casdnea, 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 nith 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- 
pldla porphyrea, 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 Ldocampa 
dictwa. Some ascend instantly to the ceiling, as 
AgrotU corticea. 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 
