124 PHILOSOPHICAL TRANSACTIONS. [aNNO 1771. 



them. The ant and the bee are both of this kind, collecting the honey in which 

 the aphides abound; but with this difference, that the ants are constant visitors, 

 the bee only when flowers are scarce. To which he also adds, that the ants will 

 suck, in the delicious nectar, while the aphides are in the act of discharging it 

 from the anus; but the bees only collect it from the leaves on which this honey- 

 dew has fallen. 



Sect. 3. — In the autumn, Dr. R. finds 3 more generations of aphides to be 

 produced; 1 of which make their appearance in the month of August, and the 

 3d usually before the middle of September. As the first 2 difl^er in no respect 

 from those which are met with in summer, it would be wasting tiuie to dwell 

 any longer on them ; but the 3d, difl^ering greatly from all the rest, demands our 

 giving it a more serious attention. Though all the aphides which have hitherto 

 appeared were females, in this 10th generation are found several male insects; 

 not that they are by any means so numerous as the females, being only produced 

 by a small part of the former generation. To which Dr. R. further adds, that 

 he has observed those which produce males, previously to have produced a num- 

 ber of females, which in all respects resemble those already described. 



The females have at first altogether the same appearance with those of the 

 former generations; but in a few days their colour changes from a green to a 

 yellow, which is gradually converted into an orange-colour, before they come to 

 their full growth. They differ likewise in another respect, at least from those 

 which occur in the summer, that all those yellow females are without wings. 

 The male insects are however still more remarkable: their outward appearance 

 readily distinguishing them from the females, of this and all other generations. 

 When first produced they are not of a green colour, like the rest, but of a 

 reddish brown ; and have afterwards, when they begin to thicken about the 

 breast, a dark line along the middle of the back. These male insects come to 

 their full growth in about 3 weeks time, and then cast off their last covering; 

 the whole insect being after this operation of a bright yellow, the wings only 

 excepted. But they soon change to a darker yellow, and in a few hours to a 

 very dark brown ; if we except the body, which is something lighter coloured, 

 and has a reddish cast. They are all of the winged sort; and the wings, which 

 are white at first, soon become transparent, and at length appear like very fine 

 black gauze. 



The males no sooner come to maturity, than they copulate with the females; 

 in which act they are readily discovered, as they remain in conjunction for a 

 considerable time, and are not easily disturbed. The commerce between them 

 continiies the whole month of October, and may be observed at all times of the 

 day ; though he has found it most frequent about noon, especially when the 

 weather is moderately warm, with the sun overcast. Tlie females, in a day or 



