INSECTS INJURIOUS TO AGRICULTURE. 209 



has discovered that, like the European individuals, it lays its 



eggs at the approach of cold weather on plum-trees near by. 



The Hop-worm (Hypena humuli Harris). In June, and 



FIG. 254. Hop-worm, pupa, and moth; all natural size. 



again in July and August, hop-leaves are devoured by 

 active, slender, grass-green caterpillars, with but four pairs 

 of abdominal legs. 



REMEDIES. Hand-picking and vigorously shaking the vines twice 

 a day, as well as spraying the vines with whale-oil soap, are advisable. 



Injuring the Grape-vine. 

 The Phylloxera (Phylloxera vastatrix Planchon). By 



FIG 255 The Phylloxera, wingless leaf-form, a, under, 6, upper, side of newly- 

 hatched larva- c egg; d, section of the leaf-gall containing the insects; e, 

 swelling of tendril; /, side, gr, upper, /i, under, view of the mother gall-louse; 

 f, antenna; j, two- jointed tarsus. After Riley. 



far the most destructive insect of the vine is this Aphid. 

 It exists in two forms, one raising irregular galls on the 



