200 INTERNAL ANATOMY OF INSECTS. 
the day-time, he finds them often perched on the lichens 
that cover the north side of the trunk of a tree, with 
their wings and antennae folded, and themselves without 
motion, and insensible of his approach and their own 
danger. Thus it was that I captured that rare insect 
the lobster-moth {Stauropus Fagi) in the New Forest. 
Some, however, have asserted that the caterpillar of the 
silkworm, except when they moult, never intermits 
feeding day or night, and consequently does not sleep : 
but the accuracy of this statement, both from analogy 
and observation, admits of great doubt. Malpighi in- 
forms us that these caterpillars for an hour and more, 
twice a day, remain immoveable with their heads bent 
down as though asleep, and even if disturbed, resume 
again the same inactive posture 2 ; and other larvae in 
great numbers certainly seem to have regular intermis- 
sions from eating of considerable duration : those called 
Geometers, for hours together remain motionless pro- 
jected from a twig, to which they adhere by their poste- 
rior prolegs alone; and the processionary caterpillars 
make only nightly sorties from their nests, passing the 
day in inaction and repose b . Bees have been often seen 
by Huber, when apparently wearied with exertion, even 
in the middle of the day, to insert the half of their bodies 
into an empty cell, and remain there, as if taking a nap, 
without motion for half an hour or longer ; and at night 
they regularly muster in a state of sleep-like silence. 
Mr. Brightwell once observed an individual living spe- 
cimen of Haltica concinnu, which appeared to remain 
motionless on the same spot of a wall for three successive 
days. 
» Be Bombyc. 5. b Reaum. ii. 185—. e Vol. II. p. 186. 
