MEMOIR. XXxxix 
flock, so like the /thomza, that the most experienced insect-hunter 
cannot detect the difference till he compares the structure of the 
mimicker and the mimicked. (Sometimes the members of one 
species counterfeit each other.) The mimicked are distinguished 
from the mimickers by their having the “same family facies,” whilst 
the mimickers are unlike their nearest allies, being “ perverted, as it 
were, to produce the resemblance from the normal facies of the 
genus or family to which they severally belong.” * Both the genuine 
and the counterfeit forms fly in the same parts of the forest, and 
generally in company, but “the Leptalzdes are exceedingly rare ; 
they cannot be more than as I to 1000 with regard to the /thomie.” f 
“Some of the imitations by insects of inanimate and living 
objects are very singular, and may be mentioned in this place. 
Many caterpillars of moths, but sometimes the cases only which are 
manufactured and inhabited by the caterpillars, have a most decep- 
tive likeness to dry twigs and other objects. Moths themselves 
very frequently resemble the bark on which they are found, or have 
wings coloured and veined like the fallen leaves on which they lie 
motionless. The accidental general resemblance between the shape 
of moths’ wings and leaves here gives nature the groundwork for 
much mimeticanalogy. It has been pointed out by Réssler that the 
buff-tip moth, when at rest, is intended to represent a broken piece 
of lichen-covered branch,—the coloured tips of these wings, when 
they are closed, resembling a section of the wood. Other moths 
are deceptively like the excrement of birds on leaves. I met witha 
species of phytophagous beetle (chlamys pilula) on the Amazons, 
which was indistinguishable by the eye from the dung of caterpillars 
on foliage. These two latter cases of imitation should be carefully 
considered by those who would be inclined to think that the object 
of mimetic analogies in nature was simply variety, beauty, or 
ornament: nevertheless these are certainly attendants on the 
phenomena; some South American Casszd@ resemble glittering 
drops of dew on the tips of leaves, owing to their burnished pearly 
gold colour. Some species of Longicorn Coleoptera have precisely the 
colour and sculpture of the bark of the particular species of tree 
on which each is found. It is remarkable that other species of the 
same small group of Longicornes (phacellocera buguetit, cyclopeplus 
batesiz) counterfeit, not inanimate objects, like their near kindred 
just cited, but other insects, in the same way as the Leféalzdes do the 
ffeliconide. 
* Tbid., p. 504. } Lbid., p. 505. 
