46 



ON THE LUMINOSITY 



readme whole passage : — " A genus, in the order Hemiptera, 

 called Fulgora, includes several species, which emit so pow- 

 erful a light, as to have obtained, in English, the generic 

 appellation of lantern flies. Two of the most conspicuous of 

 this tribe are the 6 F. laternaria and °F. candelaria ; the 

 former a native of South America, the latter of China. Both, 

 as indeed is the case with the whole genus, have the material 

 which diffuses their light included in a hollow subtransparent 

 projection of the head. In F. candelaria this projection is of 

 a subcylindrical shape, recurved at the apex, above an inch in 

 length, and the thickness of a small quill. We may easily 

 conceive, as travellers assure us, that trees studded with multi- 

 tudes of these living sparks, some at rest, and others in motion, 

 must, at night, have a superlatively splendid appearance. In 

 F. laternaria, which is an insect two or three inches long, the 

 snout is much larger and broader, and more of an oval shape, 

 and sheds a light, the brilliancy of which transcends that of any 

 other luminous insect. Madame Merian informs us, that the 

 first discovery which she made of this property caused her no 

 small alarm. The Indians had brought her several of these 

 insects, which, by day-light, exhibited no extraordinary appear- 

 ance; and she inclosed them in a box until she should have an 

 opportunity of drawing them, placing it upon a table in her 

 lodging-room. In the middle of the night, the confined 

 insects made such a noise as to awaken her, and she opened 

 the box, the inside of which, to her great astonishment, ap- 

 peared all in a blaze ; and in her fright letting it fall, she was 

 not less surprised to see each of these insects apparently on 

 fire. She soon, however, divined the cause of this unexpected 

 phenomenon, and reinclosed her brilliant guests in their place 

 of confinement. She adds, that the light of one of these 

 Fulgorce is sufficiently bright to read a newspaper by ; and 

 though the tale of her having drawn one of these insects by 

 its own light is without foundation, she doubtless might have 

 done so if she had chosen. Another species is figured by 

 Donovan, in his Insects of India, of which the light, though 

 from a smaller snout than that of F. laternaria, must assume 

 a more splendid and striking appearance, the projecting part 

 being of a rich deep purple, from the base to near the apex, 

 which is of a fine transparent scarlet ; and these tints will, 

 of course, be imparted to the transmitted light." The passage 



