between lepidopterous larve and their surrowndings. 321 
A. DARK LARVZ OF BIDENTATA ON JULY 6TH. 
I. Black sticks—Fourteen out of the 15 larvee were very 
black, the exception being quite small and probably in the 
3rd stage. These larve were the darkest of all the sets. 
I Deep blue paper spills-—These 12 larvae were very 
dark, coming next to those upon the black twigs in this 
respect. The dark purplish-black colour was also very 
uniform over the whole larval surface corresponding to the 
unvarying tints of the environment. 
IIT. Purplish-brown twigs.—These 15 larvae were slightly 
more variegated than II, in correspondence with the less 
uniform darkness of their environment. Except for this 
slight introduction of rather lighter shades these larvae 
were as dark as II. 
IV. White spotted purplish-brown twigs.—These 16 larvee 
were dark, but distinctly lighter than those of the three 
previous sets. They also varied a little, whereas the 
groups first described were more uniform. Although the 
relative lightness and the darkness of these larve, as 
compared with III, corresponded to the general effect of 
their respective environments, there was no marked 
resemblance to the special details of the twigs which 
had been carefully selected for Experiment IV. 
V. Brown twigs—The 17 larvee were distinctly brown 
and not nearly so black or purplish as the preceding sets. 
The shade of brown varied, being much lighter in the 
smaller larva. The brown larval surface was also some- 
what variegated with different shades of the same colour. 
Va. Bark overspread with a bright yellowrsh-green powdery 
lichen.—The 18 larve varied very greatly, some being as 
dark as the blackest of set I; many were variegated with 
shades of brown, harmonizing well with the environment ; 
for the lichen soon lost its green tint and became various 
shades of brown. This is the only note relating to this 
experiment which has been found. There is no doubt that 
the young larve were introduced on May 22nd or 23rd. 
VI. Lichen-covered stichs—The lichen was probably dead 
and had become much paler. These larvee too were much 
lighter than any of the previous sets, although a few 
were quite dark. Nearly all were light brown and much 
variegated with shades of brown, harmonizing well with 
the environment. 
Of the 7 sets of larva described above, the degrees of 
