522 EXTERNAL ANATOMY OF INSECTS. 
bristles*; and in a minute beetle called by De Geer 
Dermestes atomarius, the hairs of this part are said to 
form a brush. 
When insects, I mean more particularly Coleoptera, 
are about to move from any station where they have 
been at rest, the first thing they usually do, before they 
set a step, is to bring forward and expand their antenne, 
which have either been carefully laid up in a cavity fitted 
to receive them, or back upon the body: if they termi- 
nate in a lamellated knob, they separate the lamellee as 
far as possible from each other; or if it is perfoliate, the 
joints of it mutually recede. ‘The object of this is evi- 
dently to collect notices from the atmosphere, since the 
papillose part of these joints cannot be applied to sur- 
faces. When the animal begins to move, in many cases 
the antennz do the same, and continue their mofzon till 
it stops and returns to a state of repose. In the parasitic 
tribes of the Hymenoptera (Pupivora) they are kept in 
an almost constant vibration. Many other insects move 
them in all directions without any order or regularity ; 
and others, when they elevate one depress the other, 
and so proceed as if balancing themselves by means of 
these organs like a rope-dancer. I have before stated 
to you how by motions of their antenne, ants and bees 
communicate their wants or discoveries to each other, or 
make inquiry concerning any thing they wish to know. 
But as I shall have occasion to make some further re- 
marks upon this subject, when the senses of insects are 
under discussion, I shall for the present take my leave 
of it. 
* Linn. Trans. xii. t. xxi. f. 8g. 9, 10. 
» De Geer iv. 219. f. viii. £20. Clambus Fisch. 
© See Vor, II. p. 64 — 198—. 
