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 hive-bee, is elaborated by the delicate membrane which passes from the superior half of each ventral segment, and after describing an arch, unites itself to the preceding. The orange-coloured oil which exudes from the oil-beetle, (Melöe Proscarabaeus,) is secreted 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 transudation 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
