174 NOTES ON THE DRY SUMMER OF 1896. 



absence of the frog-hopper is a splendid example of how 

 differently apparently-similar insects responded to the dryness 

 of the season. The tiny eggs of the frog-hopper are deposited 

 on the branches of the furze, heath, and low-lying plants by 

 a winged female in the autumn. In this condition they remain 

 throughout the winter and right on into the following summer, 

 when, given the requisite heat and moisture, they hatch forth 

 into those small larvae which may be found concealed in the 

 frothy masses. As moisture is essential to the change from the 

 egg to the froth-producing larval stage, the total absence of 

 these creatures last summer is just what might have been 

 expected after a drought extending over nearly four months. 

 Incidentally, it may be mentioned that these larvse feed on the 

 juices of the plants on which they occur, and that the frothy 

 mass is exuded from their own body as a protective mantle. 

 Eobbed of this, the creatures soon die if exposed to the heat of 

 the sun, and should they even escape death in this manner, they 

 meet it in another, being devoured by birds, wasps, and other 

 enemies. 



In our orchards, the American Blight, or Woolly Aphis, 

 [Sehizoneura lanigera) has been a formidable foe. Supposed to 

 have been introduced into this country from America, over a 

 hundred years ago (1787), this pest, at varying intervals, works 

 incalculable mischief. Soon after its introduction, thousands of 

 apple and pear-trees were destroyed in the vicinity of London ; 

 and so many trees perished in Gloucestershire, sixty-two years 

 ago, that the cider-making industry was for a time threatened 

 with extinction. Like the work of many other insects, the 

 extent of the mischief occasioned by the American Blight 

 cannot always be determined during the season in which the 

 pest occurs. The females are wingless and covered with 

 filaments of a white waxy substance. Hiding themselves under 

 the bark and in small crevices, they impair the vitality of the 

 trees by robbing them of their life-supporting sap. As stated, 

 the injury is not always apparent the same season, for canker 

 and wounds follow, if the Blight has been abundant, and 

 eventually the trees droop and die. Young trees are least able to 

 bear these attacks, and as both apple-trees and pear-trees were 



