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 

 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, (Mel'oe 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- 

 ndation 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 



