MOTIONS OF INSECTS. 305 
be connected with the respiration of the animal, it is not 
easy to say what is the object of it. Moths, when feel- 
ing the stimulus of desire, or under alarm, set their 
whole body into a tremor. A living specimen of the 
hawk-moth of the willow being once brought me, upon 
placing it upon my hand, after ejecting a milky fluid 
from its anus, it put its wings and body into a most ra- 
pid vibration, which continued more than a minute, 
when it flew away. A butterfly, called by Aurelians 
“* The large skipper,” (Hesperia Sylvanus, F.) when it 
alights, which it does very often, for they are never long 
on the wing, always turns half-way round; so that, 
if it settles with its head from you, it turns it towards 
you. 
Others of the motions in question are merely those of 
parts. Butterflies, when standing still in the sun, as you 
have doubtless often observed, 
“ Their golden pinions ope and close ;”’ 
thus, it should seem, unless this motion be connected 
with their respiration, alternately warming and cooling 
their bodies. You have probably noticed a very com- 
mon little fly, of a shining black, with a black spot at 
the end of its wings (Tephritis vibrans, Latr., Secoptera, 
K. Ms.). It has received its trivial name (vibrans) from 
the constant vibration which, when reposing, it imparts 
to its wings. This motion also, I have reason to think, 
assists its respiration.—Some insects when awake are 
very active with their antennae, though their bodies are 
at rest. I remember one evening attending for some time 
to the proceedings of one of those may-flies (Dhryganea, 
a Peck in Linn. Trans. xi. 92. 
VOL. II. xX 
