iv 
Although every care has been taken in giving the dates of 
appearance, it is evident that some little allowance must be 
made for the difference of locality, and for our variable climate, 
and other causes, which militate against an unerring accuracy 
being always attainable. The reader is, however, requested to 
remember, should he see anything stated which is new to him, 
or hardly in accordance with his own opinions, that it has not 
been lightly adopted, but that it rests on the authority of 
experience of a much longer period than the Author's, and over 
a far more extended area. 
Time and place being the main things to be indicated in a 
Calendar, the order of the various families of Insects is of course 
much broken into; and many species in different stages are 
brought into contiguity, whose simultaneous appearance may 
have been before unsuspected. Most readers of the Calendar 
will be perfectly familiar with the leading characters of all the 
chief families ; and it is therefore unnecessary to refer to them. 
The necessity of botanical knowledge for the successful pursuit 
of Entomology has always been undisputed. Without it, the 
food-plants cannot be ascertained ; and unless a large portion of 
the Collector’s operations is devoted to rearing species through 
all their stages, neither his collection nor his knowledge can 
make that satisfactory progress which they will make if this 
more occult part of Lepidopterology is steadily pursued. The 
large number of “unknown Larve” may doubtless be greatly 
reduced by a more universal pursuit of this branch of the study. 
The time and food of several appear in the Calendar, which 
have not before been published except in an isolated form, 
“Low plants” will probably be found to yield the largest per 
centage of these mysterious strangers ; and all through the year 
they should receive the special attention of the energetic 
student. 
