HINTS UPON COLLECTING. 315 
a generic type renders its acquisition either incon- 
venient or unattainable. Few private collections, for 
instance, have space sufficient for an ostrich, a casso= 
wary, or a peacock: while the plantain-eater (JZuso- 
phaga), the Argus pheasant (Polyplectron), and a 
number of smaller birds, which at present stand as 
almost solitary examples of their respective genera, are 
so rare, and bear so high a price, that they are placed 
beyond the reach of ordinary collectors. In such cases, 
our plan is, to make slight but accurate pencil-drawings 
of the head and feet, of their natural size, whenever an 
opportunity occurs. This advantage, in most cases, 
may be enjoyed by consulting the specimens in the 
British Museum, where many of these rare birds are to 
be seen, and where they are at all times gratuitously 
opened, with alacrity and liberality, for the inspection of 
the scientific student. 
(380.) The practical naturalist, whatever he may 
think on the inutility of a collection to illustrate his 
department, will derive no small advantage from the 
power of referring to specimens at his pleasure; and 
of enabling others, by examining them, to complete 
the history of an animal, the active properties of which 
he has alone investigated. It is almost impossible, in 
fact, for a field-naturalist, when speaking of the habits 
or economy of a species, to make himself well under- 
stood unless he has sufficient knowledge of his pursuit, 
as a science, to describe the subject itself in such lan- 
guage that it may be understood by those who have 
never seen it; or unless he preserves specimens for 
future inspection. A remarkable instance, illustrating 
this necessity, has already been mentioned ; where, from 
inattention to these requisites, the naturalists of Europe 
could not make out even the order, much less either the 
genus or the species, to which the Hessian fly of the 
Americans belonged. This was the more extraordi- 
nary, since a pile of reports, pamphlets, and other pub- 
lications, had been expressly devoted to describe the 
injuries it produced. Travellers, who collect the ani- 
