Though the great majority of luminous animals are marine, frequently lighting up the breaking wave with millions of moving atoms, or spreading over the beach like a sheet of fire,[20] yet several insects are also endowed with the same wonderful property. The European glow-worms and fire-flies, sparkling on the hedge-rows, or flying in the summer air, afford a charming spectacle; but their brilliancy is far surpassed by that of the phosphorescent beetles of the torrid zone. Thus the Cocujas of South America, which emits its light from two little transparent tubercles on the sides of the thorax, glows with such intensity that a person may with great ease read the smallest print by the phosphorescence of one of these insects, if held between the fingers and gradually moved along the lines with the luminous spots above the letters; but if eight or ten of them are put into a phial the light will be sufficiently good to admit of writing by it. [Illustration: COCUJAS.] The Indian Archipelago is equally rich in luminous insects. The Podada tree, the ornament of most of the river banks of Borneo, has a remarkably elegant foliage of a light green colour. Rajah Brooke[21] describes these trees illuminated by the fire-flies in countless numbers as a most enchanting sight, and resembling a fire-work by the constant motion of the light. On the Samarahan he sometimes saw each side of the river lit by a blaze of these beautiful little insects. In the woods of Sarawak Mr. Adams observed a splendid glow-worm (_Lampyris_), each segment of the body illuminated with three lines of tiny lamps, the luminous spots on the back being situated at the posterior part of the segmentary rings on the median line, while those along the sides of the animal were placed immediately below the stomates or spiracula, each spiraculum having one bright spot. This very beautiful insect was found shining as the darkness was coming on, crawling on the narrow pathway, and glowing among the dead damp wood and rotten leaves. When placed around the finger, it resembled in beauty and brilliancy a superb diamond ring. The sparkling effulgence of the tropical Elaters is frequently made use of by the fair sex, as an equally singular and striking ornament. The ladies of the Havana attach them to their clothes on occasions of festivity, and the Indian dancing girls often wear them in their hair.