110 PHILOSOPHICAL TRANSACTIONS. [aNNO 1 684-5. 



the common glow-worm. By Ulysses Aldrovandus, lib. 4, cap. 8, it is thus de- 

 scribed: The winged glow-worm has its wings included in sheaths of a dusky 

 colour; the head, on the upper part, is covered as if with a cowl, of the shape 

 of an inverted flat shield, and of like colour as the sheaths; its little head, 

 which is quite black, is parted into two tubercles or eyes, of the same colour; 

 its tail consists of rings and is divided by several segments; in its extremity are 

 two pellucid drops, like fire, but inclining from a shining fiery colour to a green 

 or bluish one, like the flame of sulphur; and they are then best observed, when 

 on compressing the tail that transparent humour tends to its extremity, &c. 



It is much to the same purpose described by Moufet and Thomas Bartholin, 

 in his treatise De Luce Animalium ; save that they both I think mistake in al- 

 lowing the male only to have wings, whereas they both fly alike, and there is 

 no difference between them, except in size, the female being rather the larger. 

 Its light was very vivid, so as to be seen plainly when a candle was in the room ; 

 but its vibrations were unequal, and the colour greenish, like that of the creep- 

 ing glow-worm. The luminous part is two small specks on the under side of 

 the tail, at its end. The shining continued for a little while after the tail was 

 cut off, though it sensibly decayed, till at last it became quite extinct. Possibly 

 the use of this light is to be a lantern to the insect in catching its prey, and to 

 direct its course by in the night, which seems probable from its position on the 

 under part of the tail, so that by bending it downward, it throws a light for- 

 ward on its prey ; while the luminous rays in the mean time do not at all incom- 

 mode its sight, as they would have done had this torch been carried before it. 

 This conjecture is also favoured by the placing of the eyes, which are on the 

 under part of the head, not on the top. I observed also that it could and did, 

 by some contrivance, cover its light, and make a kind of dark lantern. 



Fig. 7, pi. 3, shows the insect on its feet, with the back upwards, where it 

 appears to be of the beetle kind ; it is of a dark brown colour, unpolished ; 

 when the case-wings are opened it extends two very large membranous wings, 

 fastened to the upper part of the thorax ; its head is covered as it were with a 

 shield or broad-brimmed hat. Fig. 8, represents it laid on the back, to show 

 the two eyes under its cowl or hat ; they are black and very large, making up 

 almost the whole head, there being little else to be seen ; these are moveable, 

 so that the animal can thrust them forward to the edge of its hat. From be- 

 tween these are discovered the two hairy feelers, or perhaps brushes to cleanse 

 the eyes. Between these eyes and the thorax lies the mouth, on the thorax are 

 6 legs, almost all of a length. The tail consists of 7 shelly rings, on the last 

 of which are visible the two shining points. Fig. Q, shows the insect on its 

 back, as seen through a microscope when dead; where A A represents the two 



