226 Agkicultural Experiment Station, Ithaca, N. Y. 



to attract attention. Their work, however, soon becomes apparent. 

 Minute semi-transparent darkish spots appear on the terminal leaves. 

 These spots are scarcely larger than a common pin's head, and are round 

 or slightly angular in shape depending upon the direction of the minute 

 veinlets of the leaf which bound them. The insect has inserted its beak 

 into the leaf and sucked out nearly all of the opaque green pulp or 

 parenchyma of the interior within a small area bounded by the little 

 veinlets. (Fig. 2.) The upper and lower epidermal layers of the leaf 

 are not disturbed, except where the beak was inserted through 

 one, and when the interior pulp is withdrawn these layers soon 

 collapse, thus giving the spot a slightly depressed appearance. For 

 two or three days these spots are not very conspicuous, as they differ 

 but little in color from the remainder of the leaf. Soon, however, the 

 collapsed epidermal layers turn brown and die, thus rendering the spots 

 quite opaque and conspicuous. They are slightly more noticeable on 

 the lighter lower side of the leaf than on the upper side. 



As the insects increase in size they suck out the parenchyma from 

 larger areas, the spots then often measuring one-tenth of an inch in 

 diameter. If one insect confines its attack to a single leaf for some 

 time, or when more than one works on the same leaf, the>e spots often 

 coalesce and frequently the whole leaf turns brown, curls up and dies; 

 being brittle it is often torn and broken by the wind. (Fig. 1.) In 

 1892 the injury to the currants and gooseberries in the horticultural 

 garden here reached this stage and the whole field looked as though .i 

 fire had swept quickly through and killed the terminal leaves. When 

 all the tenderest leaves have succumbed, the insect continues its attack 

 on the older leaves lower down. During its lifetime a single insect 

 will destroy at least two or three currant or gooseberry leaves. This 

 accounts for the fact that the injury wrought often seems much out of 

 proportion to the number of insects at work. 



When the insects are very numerous, the growth of the shoots is 

 often checked, they droop, wither and die. Some have thought that 

 this blasting of the growth was caused by a poisonous saliva which the 

 insect injected into the wound made by its beak. However, it is more 

 probable that the shoot dies or its growth is checked on account of the 

 death of its breathing organs — the leaves. On the currant, gooseberry 

 and many other plants, the insect confines its attacks to the leaves, but 

 on some ornamental plants, as the dahlia and rose, the most frequent 

 point of attack seems to be the buds. This peculiar phase of the 

 attacks of the pest has been described in the discussion of the past 

 history of the insect. 



