524 SEASONS OF INSECTS. 
for me some memoranda he had made with respect to 
the sudden appearance of Ccrcopis bifasciata. On one 
occasion the white dress of a lady sitting upon a hay- 
cock was covered by these insects; but on the following 
day the same steps were taken at the same time to pro- 
cure some, when after the most diligent search not a 
single one could be found. The same circumstance was 
observed a few years afterwards by another friend of his. 
He himself was of opinion that the insects in question 
were then migrating 2 . 
I may here observe, that the London amateurs have 
particular seasons for collecting moths. For the imago 
they go into the woods in April, May, June, and Octo- 
ber. For the larvae they take the beginning of April, 
June, the beginning of July, and September. They dig 
for pupa late in July, and in January and February. 
I shall lastly make a few observations upon the times 
of action and repose of insects, the knowledge of which, 
as far as it can be obtained, is of essential use to the in- 
dustrious collector. Entomologists have divided the Le- 
pidoptera, with a view to this circumstance, into diurnal, 
crepuscular, and nocturnal ,- or butterflies (Papilio L.), 
hawkmoths (Sphinx L.)» and moths (Phalcena L.). These 
terms may be applied to insects in general. 
i. Diurnal insects are abundant. Butterflies in parti- 
cular fly generally at no other time: they accompany the 
sun in his course, and before he sets disappear. Some 
other Lepidoptera, though not so named, are day insects : 
— such are the Zygcenida, &c. amongst the hawkmoths ; 
' Vol. II. p. 11. 
