556 INVESTIGATION OF INSECTS. 
liarities: but this is not, and cannot be, done so as to re- 
present every one. But though in general figures should 
be your last resort, I know not whether an exception to 
the rule may not be advisable with respect to the Lepzdo- 
ptera, which are more difficult to be intelligibly described 
than any other order of insects; while a good figure exhi- 
bits to the eye all those markings and shades, that scarcely 
any description can place clearly before the mind. 
When every attempt to investigate the name of your 
unknown species fails, and you have consequently reason 
to believe that it is undescribed, the best mode you can 
pursue for retaining that knowledge of its characters, 
which from your long investigation you must have ac- 
quired, is to note them down in your entomological 
journal, inserting it under its proper genus with a tri- 
vial name of your own. Such a journal you will find 
almost a sine qua non for containing a catalogue of your 
insects, and to register any observations concerning indi- 
viduals you may have had an opportunity of making. 
With regard to this journal, I should recommend to 
you to get two blank books. One a duodecimo of 200 or 
300 pages, to contain the mere catalogue of your insects, 
their habitat and localities, or the source from which you 
derived them. In this you should number the genera in 
Roman capitals, and the species under each by a figure ; 
leaving considerable space at the end of each genus for 
the insertion of new species. ‘The other book should be 
of an octavo size, containing 400 or 500 pages. Under 
the number of each genus and species you might de- 
scribe and figure it, if undescribed ; if described, note in 
what it varies from the description, and what characters 
are overlooked : and in general insert such observations, 
