Mr. F. Walker on the Migrations 0/ Aphides. 373 



sloe, and the hop-grounds now provide it with a plentiful 

 provision in the summer. Its presence on the hop is depen- 

 dent on the proximity of the sloe to the hop-grounds, and these 

 plantations should be inspected, and the extent of the sloes 

 in the vicinity and their distance from the hops ascertained, and 

 the length of the flight of the Aphis should also be observed, 

 in order that the hop and the sloe may in time be kept suffi- 

 ciently remote from each other to confine the Aphis to the latter 

 plant and thus to prevent its injuring the hop. A. Ulmarice 

 dwells on the broom, and the meadow-sweet is its summer food, 

 and the cultivation of sweet peas, peas, beans, clover, tares, 

 vetches, saintfoin, &c. has added greatly to its means of subsist- 

 ence. A. Lactucce is very abundant on the sow-thistle and some 

 allied plants, and its oeconoray is modified by the presence of the 

 lettuce and the black currant in gardens, to both which plants 

 it is very partial. A. Brassica feeds especially on the sea-kale 

 in a wild state, and also on the wild mustard, and the introduc- 

 tion of the cabbage from the South of Europe has added to its 

 food in this country. A. Pruni has settled on the plum since 

 that tree was brought into Europe, and it has received the name 

 of A. Arundinis from its feeding on the reed, which is its earliest 

 habitation. A. Mali and A. Sorbi dwell on the white-thorn as 

 well as on the apple, the service, the medlar and the mountain- 

 ash. A. Persicce is so named from its having fixed itself on the 

 peach since that tree was planted in Europe, but its other name, 

 A. Prunicola, denotes its primitive habitation and food. A. 

 Juglandis and A. Juglandicola have accompanied or followed the 

 walnut in its successive cultivation westward from Persia, which 

 is its native country, and that of the peach and of the apricot. 

 A. Abietina has probably come into England with the spruce fir, 

 and a few other species that feed on the fir-tribe may have also 

 been brought over from the continent. A. Ruhi abounds on the 

 bramble and on the raspberry, and during the summer is also 

 common on Geum urbanunij the common Avens, and on a species 

 of Epilobium or willow-herb. A. Dianthi (otherwise named A. 

 vulgaris and A.RapcE and A.vastator) feeds on a very great variety 

 of green-house plants. The furze seems to be the principal 

 winter-quarters of A. Rumicis, and I observed that it swarmed 

 profusely and laid its eggs on that plant in the autumn of 1846, 

 and the following year was remarkable on account of the devasta- 

 tions of this Aphis in the bean-fields ; it feeds also on the labur- 

 num, the poppy and the dock, and on very many other plants. It 

 was unusually abundant on the laburnum last year, and great 

 numbers of humble-bees came to feed on its honey. The lady- 

 bird [Coccinella 7 -punctata) was also extremely common with 

 this Aphis, and it promises to be equally so this year, for great 

 numbers have already appeared during March and April 



