INSECTS INJURIOUS TO TOBACCO. 225 



become numerous enough to be injurious during the first 

 two weeks in June, usually being first noticed in one 

 corner of a field, from which they rapidly spread over the 

 whole. The eggs are deposited singly, in the tissues of 

 the leaf, mainly on the smaller veinlets, and hatch in 

 about four days. The young nymphs at once attack the 

 foliage, and after molting about four times transform to 

 adults about eleven days later. The full-grown njmiphs 

 are of the same general aj^pearance as the adults, except 

 that the wings are still undeveloped and form small wing- 

 pads, but are of a greenish color. As it requires but a 

 fortnight for the development of a brood, these insects 

 multii^jy very rapidly and in a few weeks become so 

 numerous as to seriously damage the foliage, hundreds of 

 them being found on a single leaf. The injury is done by 

 their inserting their small beaks into the tissue of the leaf 

 and sucking the juices, causing the leaf to become yellowish 

 or wilted, and cracking older leaves so that they become 

 ragged. "Experienced growers say that the leaves badly 

 infested with the Suck-fly are very difficult, if not impossi- 

 ble, to properly cure.^' The weather plays an important 

 part in the control of this pest. ''According to an 

 observant grower, ' an important factor in bringing about 

 their disappearance has been the absence of rain duriiio- 

 the latter part of August and early September. The sticky 

 exudation from the glandular hairs of the tobacco-plant 

 causes many of these insects to become stuck to the leaf 

 and in this way a great many are killed. Frequent showers 

 keep this washed off to a considerable extent, and thus 

 favor the insects.^ ^' (Quaintance.) A veritable fl3^-trap ! 

 Remedies. — In experimenting with insecticides for this 

 pest, Prof. Quaintance has found, curiously enough, that 



