478 MRS. O. A. MERRITT HAWKES ON THE 



lias a grey-green mealy exudation, which tills the stoniata of the 

 iarvse and so kills them. When a Victoria plum was covered with 

 this aphis, no larvje or imagines were ever found among them, 

 and very few larvaj of the Hover- fly, which is probably an even 

 more prolific eater of aphis than the Coccinellida?. 



The presence of large numbers of Coccinellidse on the Stinging 

 Nettle may be due to the fact that these insects are not univer- 

 sally carnivorous, C. sejMrapunctata certainly eats the abundant 

 pollen and possibly other products of this plant. Donisthorpe 

 found that C. distincta ate the honey supplied to ants, and I 

 have found G. sepiem2mnctata eat the exudation from bean plants 

 and Jerusalem artichokes in the autumn. During the summer 

 I have observed A. bipunctata 'a.^-p^rei\t\y eating the juice of rasp- 

 berries and split plums. 



The Aclalia larvfe in the first two instars have to be fed with 

 minute aphis, as, although sufficiently pugnacious to attack large 

 aphis, the latter can easily shake them ofT. 



Any species of aphis were used in 1918, but in 1919 practically 

 two species only —in early summer Aphis pruni Fab., which attacks 

 damson-trees ; and for the remainder of the year Aphis fagi, 

 which lives only on the beech. Although the latter is slightly 

 woolly when full grown, it is in the earlier stages very acceptable 

 to hipimctata. The copper-beech is attacked more frequently 

 than the green beech, and on the former numbers of biptmctata 

 are to be found all the summer. The supply of beech aphis has 

 the advantage of being fairly constant, as the leaves and branches 

 are so flat and so close together that it takes a great deal of cold 

 and rain to clean the aphis off the tree. The flat leaves, which 

 do not wither readily, are very siiitable in boxes. The aphis of 

 the rose (Siphonot-a rosce) and of the nettle {Aphis urticia) both 

 die quickly in boxes, presumably owing to the wilting of the thin 

 leaves of the food-plants. 



In August 1920, after a variety of expeiiments, I found that 

 the adults will eagerly eat pounded dates, upon which they can 

 live for months. The newly hatched larvse cannot use this food 

 at all, but I succeeded in bringing one larva from the second 

 instar to the perfect insect on dates alone, the imago being of 

 avera,ge size. Most of the older larvae kept alive on this diet for 

 some time, but did not grow much and ultimately died. 



I have obtained the best results by feeding in closed boxes. 

 The boxes must be opened every day, not only to introduce fresh 

 food but also fresh air, which is of paramount importance to this 

 species. Great care has also to be taken to I'emove all mouldy 

 leaves. A mould (probably Gladosjiorium cqjhidis Jhiim) quickly 

 grows on the honey-dew produced by the aphis, especially that 

 found on beech and sycamore leaves. This mould fatally attacks 

 the larvse. It first appears on the thorax, but its method of 

 producing death is undetermined. 



The main difficulty of rearing is the cannibalistic habit of not 

 only A. bipunctata, but also C. septempiinctata, C. variabilis, and 

 H. li-punctata. The larvfe eat eggs and one another in either 



