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 antenna 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*; 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 5 . 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 concinna, which appeared to remain 

 motionless on the same spot of a wall for three successive 

 days. 

 * De Bombyc. 5. b Reaum, ii. 185. c VOL. II. p. 186. 



