24 REPORT ON INJURIOUS INSECTS FOR 1907. 



With this object in mind, various experiments have been made with 

 a view to providing a Fluid that will confer immunity upon the plants 

 against the attack of these insects for a number of days, without injuring 

 the bine. 



Whilst I believe the experiments are on the right lines and will 

 ultimately prove successful, I have not yet arrived at any satisfactory 

 conclusion. The experiments, however, will be continued during the 

 coming season and duly reported upon. 



THE WILLOW APHIS. 



Lachnits viniinalis, Fonsc. 



In July last I received some willow twigs from a Worcestershire 

 correspondent covered with this aphis. W T hen examined in September 

 the trees were perfectly free from this pest, although the harm it had 

 done was easy to see. 



I am not aware that the life-history is known, but in the autumn 

 I find that there is a general migration from the willows, probably to 

 some other plant or plants, at present unknown. Sometimes, on 

 appearing on some species of willows, little damage is done ; arid the 

 insects will then migrate to other species, which suffer considerably. 



THE WOOLLY APHIS. 



Schizoneura lanigera, Hausm. 



This insect has been very plentiful during the past year in all the 

 Midland counties. 



In 1896 Mr. J. M. Stedman (l1 published a full and interesting 

 account of its life-history, and the present year has afforded me an 

 excellent opportunity to w r ork through this life-history in England, and 

 compare it with the above admirable account. 



For this purpose a garden containing some score of badly infested 

 apple trees was selected, and further observations have been made in 

 numerous orchards, as well as in the laboratory. 



LIFE- HISTORY. 



Throughout the year there may be found on the trees a somewhat 

 oval shaped aphid of a purplish or reddish brown colour. This is the 

 " Queen-mother " which secretes the characteristic woolly material. 

 She gives birth to living young, minute, louse-like forms of a greyish- 

 yellow colour. These larvae, at first, live beneath the woolly secretion 

 close to the parent ; but after a time they creep away, form great 

 masses of wool, and produce a further generation of living young. 

 This mode of reproduction is continued throughout the summer, when a 

 resting stage is reached, and pupae, or nymphs appear, which give rise 

 to winged forms. 



(i) Agric. Exp. Stat. Univ. of the State of Missouri, Bull. No. 35, 1896, pp. 36-61. 



