I never rightly understood till now that the glow-worm is the female fire-fly, though it looks just like a worm, and does not fly. My aunt showed me to-day that this insect, though it possesses neither wings nor elytra, and differs but little in appearance from a caterpillar, is, notwithstanding, an insect in the last or perfect state: the head and corselet are formed exactly like those of the male, who is furnished with both elytra and wings. My aunt also showed me that under the last ring of the body there are two very small reservoirs of a thick oily fluid of the nature of phosphorus, which, if the animal is killed, continues to give light till it becomes dry. It is a slow-moving creature I am told, and seems to drag itself on by starts or slight efforts.
My uncle says that in the Philosophical Transactions for 1684, there is a paper by a Mr. Waller describing an English flying glow-worm, which he observed at Northaw, in Hertfordshire, the light of which was so vivid as to be plainly perceived even when a candle was in the room.
Mary put a common glow-worm into a box of transparent paper with some grass and moss, two days ago, and when we went to examine it last night we saw its beautiful light illuminating every object within a small space around it.
When I saw the glow-worm shining on its mossy banks, I amused myself in imagining how many other living creatures were perhaps lighted by its soft beams. The various beetles, which seem at all hours running to and fro; the slugs, which are for ever in one’s path; and the numerous family of spiders, who are so industrious, that they must, I suppose, work “by midnight lamps.” The moth tribe, also, who seem to love light only at night, can please themselves at this little lamp, without injuring their delicate wings; and I must not forget the little airy beings, of whose histories I am so fond—the fairies—who say so prettily—
And when the moon doth hide her head,
The glow-worm lights us home to bed.
Frederick and I were devising various expedients for making the light of the glow-worms and fire-flies useful; when Mary, who heard us, told me that at Cape Comorin there are certain birds that build pendulous nests; and that it is a fact that these nests are lighted, at night, by fire-flies: the bird fastens a bit of clay to the top of the nest, and sticks a fire-fly on the clay, as if to illuminate the dwelling, which consists of two chambers; but the real object is, probably, to deter the bats from approaching, as they kill the young of these birds. This is mentioned in the life of Dr. Buchanan, who says that the blaze of light dazzles the eyes of the bats. A friend of my uncle’s has written some lines on the glow-worm, which I will copy here.
TO THE GLOW-WORM.
Thou little gem of purest hue,
That, from thy throne o’erspread with dew,
Shedd’st lustre o’er the brightest green
That ever clothed a woodland scene,
I hail thy pure and tranquil light
Thou lovely living lamp of night!
Thy haunt is in the deepest shade
By purple heath and bracken made:
By thee the sweetest minstrel sings,
That courts the shady grove;
O’er thee the woodlark spreads his wings,
And sounds his notes of love
Companion of the lights of heaven!
Thine is the softest breeze of even;
For thee the balmy woodbine lives,
The meadow-grass its fragrance gives.
And thou canst make thy tranquil bower
In Summer’s sweetest, fairest flower.
The hour of peace is all thy own;
Thy lamp is lit for one alone;
Shedding no transitory gleams,
No rays to kindle or destroy;
Constant, innocuous—still it beams
The light of life, of love, of joy.
My aunt has been so kind as to permit me to make an extract from my cousin Hertford’s last letter to her. I enclose it with my journal, which my uncle is going to dispatch to-morrow.
“At last I have overcome every obstacle; and have visited Staffa and its curious caves.