NATURE STUDY. 
A MONTHLY BULLETIN OF THE 
Manchester Institute of Arts and Sciences. 
Vol. I. AUGUST, 1900 . No. 3 . 
A Rural Impostor. 
BY CLARENCE MOORES WEED, DURHAM, N. H. 
In tropical countries, as every one knows, there are many in¬ 
sects that mimic their surroundings. Wonderful tales are told 
by travellers of cunning creatures which so closely resemble 
leaf or twig or bark that it is impossible to distinguish them. 
But it is less generally known that in our own fields and woods 
there are many examples of such mimicry as wonderful as those 
of the tropics. In this brief sketch I wish to bring to light one 
such impostor. 
Over a large part of the eastern region of the United States 
the fields and roadsides are overrun by a sweet fern, a low- 
growing shrub familiar to every one who has rambled through a 
New England pasture. It is a vagrant plant, not at all choice 
as to its situation, speedily taking possession of any unused 
land. It serves as host — presumably an unwilling one—to 
quite a list of insects that find good feeding ground upon its 
leaves. One of the most interesting of these is a strange cater¬ 
pillar— a caterpillar in disguise, for it is strikingly different 
from its kindred. 
Now caterpillars in general are smooth and cylindrical crea- 
