6 
HOP APHIS. 
I 
Observations as to the Hop Aphis migrating from Plum and Sloe. 
In the following observations the Hop Aphis is noted as migrating 
from Sloe, Plum, and other trees. With regard to the Sloe and other 
kinds of wild or cultivated Plum there appears no reason why this 
should not be the case. 
Our own observations this year have shown that Hop Aphis is to 
be found infesting the Plum, and previously to this notes have been 
published by three well-known German entomologists, stating respec¬ 
tively that the Hop Aphis is found on Sloe, and therefore Sloe bushes 
ought not to be left near Hop-grounds* * * § ; that this Aphis is to be 
found in May in great numbers beneath the leaves of the Plum and 
Sloe, and that in the month of May they (the AjjMs Humuli) leave the 
Plum leaves and betake themselves to the Hopf ; and the third states 
that the Hop Aphis is to be found from July to September in large 
numbers on the Hop, and that he has seen this on Sloe bushes in 
May 
Our own countryman, Francis Walker, states that the Hop Aphis, 
the Aphis ( Phorodon ) Humuli, “ migrates in early spring from the Sloe 
to the Hop plant, and again leaves the Hop in autumn to go back to 
the Sloe.” § The first note is as follows :— 
“ I have been a Hop grower forty years, and have ever paid great 
attention to the Hop blight, carrying a magnifying-glass, and many 
times a day examining the earth round the hills and the plants from 
top to bottom ; also the hedges, bushes, &c., the grass along the 
hedges, and wherever I could get a clue towards destroying the Aphis 
before it attacked the Hops. 
“ I do not think the eggs are deposited in the earth round the hills, 
as there are never Lice on the plants first, but Fly; the Lice come 
from the deposit of the Fly. 
“ The Fly comes from other sources. I have always found them on 
the Maple, Damson, Sloe, &c., as Lice first, and when they come into 
Fly they take wing to the Hops, and settle on the tips of the plants, 
on three or four of the upper joints where the young leaves are tender. 
They do not get on the bottom of the plants, except the wind blows 
them off on the ground. The blight attacks the Hops near the 
above-named trees first, and more severely.” — Horace Coleman, 
Brede, Sussex. 
“ My experience is, an egg in the first place is deposited on plants 
such as Plums, Blackthorn, and Willows. Later in the season that 
* ‘ Praktische Insecten Kunde,’ Dr. E. L. Taschenberg, part v., p. 50. 
f ‘ Die Pflanzenlause Aphiden,’ C. L. Koch, pp. 115, 116. 
+ ‘ Die Pflanzenfeinde,’ J. H. Kaltenbacli, p. 534. 
§ ‘ Annals of Nat. Hist.,’ xx., p. 209, 
