198 Z. G. SOLOMIDES. 



its beak a faint black spot is formed, and when an insect remained for some time with 

 its beak dipped in the pulp, on its withdrawal a deep black spot was visible. In 2-4 

 days this becomes a clear coffee-colour, and later on, it assumes a cork-hke appearance 

 and projects beyond the skin surface. This scab can be easily detached by the finger 

 nail, and microscopical examination shows that it is not the outer skin of the grape, 

 but is composed of dead tissue or pulp. I have found that the tissue was destroyed 

 to a depth of about 15 mm., and all the cellules and tissue of the pulp round the part 

 affected were of a yellowish coffee colour. 



These scabs vary in shape and size, as also the number of them found on a grape. 

 I have noticed 10 larvae on one grape quietly sucking the juice. Grapes so attacked 

 either do not develop, or they dry up ; when more lightly attacked they develop, 

 but owing to the presence of these spots, they are disfigured and are unsaleable. In 

 serious attacks 50 per cent, of the fruit may be spoilt. In cases such as these, the 

 flow of the sap is interfered with, and we may find new flowers and small grapes 

 appearing in July and August ; these furnish fresh food for the 2nd and 3rd genera- 

 tions of the insects. 



I have observed no attack on any of the woody parts of a vine or on the roots. No 

 vine attacked by this insect was found by me with diseased roots. This furnishes 

 additional proof that the damage to the plants was caused by the insects. 



The insect appears when the vine puts forth the first buds and leaves, and eggs 

 are then laid on the leaves or opening buds. Hatching takes place in 2-5 days. 

 Vines attacked early present a more injured appearance than do those which are 

 attacked only after the formation of the first shoots. In the latter stage the insect 

 finds the leaves and shoots rather hard and the rostrum cannot do so much damage. 

 This is the first generation and it appears in April. The second generation occurs 

 in May and June, when the damage is equally serious, because all the insects attack 

 the flowers and the young fruits. Up to 90 per cent, of the fruit on a vine may be 

 injured, the insects attacking cluster after cluster in turn. When they have com- 

 pleted their attack upon one vine they proceed to another. Often many plants 

 together are found so damaged. Elsewhere again the attack is confined to isolated 

 plants ; this often being due to the insects having been carried by wind. When 

 this is so, we often find that in the following year the attack is not so serious as in the 

 first year. The attack of this second generation lasts up till the first days of August, 

 when the third generation appears. This generation occurs throughout August and 

 continues until the faUing of the leaves. Then the adults hibernate in the crevices 

 of the main stem, in the side branches, or in the ground, until the following April, 

 when again the first generation appears and renews the life-cycle. 



I have noticed different Acari as parasites on Cryptothrips brevicollis, but owing to 

 pressure of other work I have not studied them. 



The following preventive measures are recommended : — 



1 . Clear the vines from weeds ; collect and burn all leaves, or let them be 

 consumed by stock. This gets rid of a large number of insects. 



2. Clear the old bark from the main stems and burn it ; apply a 15 per cent. 

 Ume wash to these stems. Possibly 80-90 per cent, of the insects hibernating there 

 would thus be killed. 



