1838. HOUSE— No. 72. 99 



by eating holes through the leaves. When living it has the power of 

 changing its hues, at one time appearing only of a dull yellow color, 

 and at other times shining with the refulgence of polished gold. To 

 ascertain the immediate source of this voluntary and evanescent 

 brilliancy, we must examine the structure of the insect. The elytra 

 or wing-cases, the parts which exhibit the phenomenon, are lined be- 

 neath with an orange-colored paint, which seems to be an organized 

 substance. On examining it with a microscope, several large vessels 

 may be perceived running to the tip from the base of the elytra, 

 where they appear to communicate with the abdomen. These ves- 

 sels ramify in the orange-colored substance, and seem finally to ter- 

 minate in numerous points with which the elytra are studded. It may 

 be remarked, that the external margins of the elytra never exhibit any 

 change of color ; they are, in fact, destitute of the paint, and are near- 

 ly transparent. The disc of the elytra appears also quite diaphanous 

 when this colored substance is removed by a knife. And further, the 

 color of the paint is most vivid when the insect is most effulgent, 

 more faint when the lustre is temporarily withdrawn, and quite dull 

 when the insect is dead. This organized substance, then, is the 

 immediate source and seat of the corruscation. Those insects which 

 shine in the night are provided with a set of organs which secrete a 

 luminous fluid. This insect, however, is brilliant during the day, 

 and its internal structure is so delicate as to defeat any attempt to 

 investigate it. The remote cause, therefore, is at present obscure. 

 It may, perhaps, be referred to a secreted fluid, which the insect at 

 will propels into the vessels that ramify in the pigment, which, when 

 thus injected, would become more opaque, and would produce a 

 different reflection of light. If such a fluid really exists, which is 

 very probable, it must have its appropriate glands or secreting organs 

 within the abdomen. How extremely minute and how wonderful 

 then must be their organization, since it is not perceptible by the 

 microscope, and is known only by its beautiful effects. These un- 

 doubtedly answer some important end, as they are closely connected 

 with the existence of the insect, and evidently appertain to the func- 

 tions of vitality. 



The last family of Coleopterous insects which will be examined 

 may be called GaleruciadcB. It is characterized by having the feet 



