VOL. LIV.] PHILOSOPHICAL TRANSACTIONS. Ill 



sion, and on their age, because they grow from day to day darker and more 

 hairy. No mouth is to be seen, but a deep plait or furrow at the upper part of 

 the breast. Two extremely small dark points seem to be the eyes. The two 

 antennae are thick, twisted like a screw, of the length of the breast ; they end in 

 an obtuse point. The 1 fore legs are twice the size of the 4 hinder legs, they 

 have all sharp black incurvated claws. It is impossible to find marks of the sex; 

 and though they join sometimes their anusses, yet they do it so loosely, that it 

 cannot be accounted for a copulation. They seem to eat nothing at all. They 

 creep about the plant a week or two, going often under ground, and getting up 

 again. Then they make themselves a deep cylindrical hole in the sand, down to 

 the hard bottom of the pot, the end of which they cover with a fine white silk 

 growing on their bodies. There they lay their eggs and die. Others, who are 

 disturbed in their work, grow weary and white, as if they were powdered all 

 over with a white meal, which through a glass appears to be very fine white 

 silky hairs, coming out all over the body. At last they lay them down on their 

 backs. — The silky hairs grow very fast, to the length of one inch and a half, 

 and the insect twists with its claws the hairs all round its body, so as to resemble 

 a small heap of cotton ; but the hairs are so tender, that a small wind will tear 

 and destroy it. In this heap of cotton they lay their eggs, from 50 to 100, 

 and then they die. Thus they remain till the middle of July. Afterwards, 

 though they make their holes, or their cotton heaps, yet they die without laying 

 eggs.^ The eggs are crimson, transparent, scarcely visible, long, and round- 

 pointed at both ends. In a week's time the young insects creep out : they are 

 like their parents, but smooth, transparent, and crimson. He presented them 

 every day fresh roots of the polygonum, but he could not say they eat any of 

 them. In a week or two they disappeared, going under ground. The insects 

 seemed then all dead, and so did the young ones, buried up in sand: but he hoped 

 next spring to see them alive, and to prosecute their further change. He killed 

 about 100 of the insects in hot vinegar, as it is done in Mexico ; and meant to 

 attempt to dye some w )ollen threads in the common way of the scarlet dyers. 

 In the microscopical observations of Ledermuller at Nuremberg, there are 

 tolerable drawings belonging to this subject. In the beginning" of August he 

 found an extremely small white fly, somewhat like to what is supposed to be the 

 male insect. It is a third part of the size of what is represented by Leder- 

 muller. It has a body like a gnat, snow-white, powdered below, but shining 

 grey on its back, 6 tender snow-white legs without claws, a thick bulky head, 

 two very small prominent eyes, two hair-like attennae, two wings, large enough in 

 comparison to the body, snow-white below, and shining grey above. The belly 

 to the tail is taper, and at the tail are 3 white hairs, very tender, and 4 or 3 

 times the length of the whole fly. But as this was the single one among 300, 



