OF INSECTS. 
169 
function is sometimes executed by the articulating 
membrane of the abdomen and limbs. Thus the 
wax, which is secreted by the neuters of the common 
Live-bee, is elaborated by the delicate membrane 
which passes from the superior half of each ventTal 
segment, and after describing an arch, unites itself to 
the preceding. The orange-coloured oil which exudes 
from the oil-beetle, ( Meloe Proscar abacus, ) is secre- 
ted by the membrane which connects the thigh with 
the tibia ; and examples of a similar nature are not 
of unfrequent occurrence. The white filamentous 
or cottonny substance which covers the body of many 
aphides, is probably of the same nature as wax, as 
well as the peculiar efflorescence observable on many 
coleoptera. The latter often forms regular designs 
on the surface, (as in Lixus , Cleonus, Eurychora,) 
which can only arise from a particular disposition of 
the pores through which the substance obtains a 
passage. 
Lac , a substance of well-known utility in the arts, 
as entering into the composition of varnish, sealing- 
wax, &c., is the glutinous and semitransparent trans- 
udation of the Coccus lacca, which envelopes its whole 
body after it has fixed itself to the branch of a tree, 
according to the manner of its congeners. 
An endless variety of scents are emitted by insects, 
some of which emanate from the fluids already alluded 
to, while others transpire in the form of invisible 
effluvia, from all parts of the body. Many of them 
are highly penetrating and diffusive, so that they can 
be felt at a considerable distance. Some of them are 
