222 THE ENTOMOLOGIST. 



Much careful observation and experiment has been devoted 

 to the hop aphis, and Miss Ormerod thinks there is good reason 

 for believing the course of attack to be as follows : — 



" 1st. That the first attack of Aphis to the hop begins in spring from 

 wingless females (depositing living young), which come up from the hop-hills. 

 2ud. That the great attack, which usually occurs in the form of * fly ' about 

 the end of May, comes on the wing from damson and sloe, as well as from 

 hop, and that the hop aphis and the damson hop aphis are very slight 

 varieties of one species, and so similar in habits as regards injury to hop 

 that for all practical purposes they may be considered one. By hop and 

 damson hop aphis I mean the Aphis {Phorodon) humuli, Schrank, and the 

 Aphis [Phorodon) humuli, var. Malaheh, Fonsc. ; but in no case the Aphis 

 Pruni, Reaum., or any other kind. 



" Further, it has been shown by the result of various experiments on 

 the hop-ground at Stoke Edith Park, Hereford (allowed us by the kind 

 courtesy of the Lady Emily Foley) that the use of various applications 

 round the hills in the late autumn, or about the beginning of April in spring, 

 completely prevents attack to the bines of those hills until the summer 

 attack came on the wing." 



Miss Ormerod differentiates between the two species and 

 gives figures, which we are kindly permitted to reproduce. 



" Now, looking at the history of the hop aphis and of the damson hop 

 aphis side by side, we find them starting at the same time in spring 

 respectively on their several plants, continuing similarly to increase ; and 

 similarly, about the end of May, to gain the winged state ; and up to this 

 date, by constant microscopic examination, I did not find any difference in 

 the frontal development of the young lice of the kinds under consideration 

 when first produced, nor in that of the winged females. The accompanying 

 figures, [Fig. I.] drawn from life, show the similarity." 



;«, ;|; ;t- ^ jjy «l, 



" From the latter part of March onward to about the time of the 

 appearance of the fly, I found that the hop-lice had the frontal tubercles 

 and enlarged root-joint, as in fig. I., this sketch being a representation of 

 large numbers sent me from infested hop-plants, and I could detect no 

 difference in form between the lice from hop-plants and those from sloe or 

 damson. At the time of flight from the sloes I figured the wingless 

 females and pupae (or larvag containing young) from hop-plants, and also 

 from damson or sloe, and noticed a slightly greater amount of gibbousness 

 in the root-joint of the antennae of the hop aphis, but, as shown in Fig. II., 

 this difference is very slight. But, continuing the observations after a time, 

 I found a difference in amount of development of these frontals in some of 



