9 



females, and with the death of these winged individuals, which soon follows, 

 the race becomes extinct for the season." 



The eggs are not destroyed by cold or wet; and drought is favorable for the 

 multiplication of those lice born in the summer, and wet unfavorable. Hence 

 their rapid increase in droughts. The effects of the attack of these lice on the 

 hop-vines is thus described in Morton's Cyclopcedia of Agriculture : 



" When the first attack of these upon the hops is severe, and early in the 

 season, the growth of the plant is commonly stopped in the course of three or 

 four weeks. If the attack be late — that is, about midsummer, or afterward — 

 the bine has then attained so much strength that it struggles on against the 

 blight to its disadvantage, and the result is a total failure of the crop at last; 

 for the leaves fiill off, and the fruit-branches being already formed, there is no 

 chance of recovery. At this time and in this condition the stench from the hop 

 plantation is most offensive. In an early blight, however, we have many in- 

 stances recorded of extraordinary recoveries; for these insects are remarkably 

 susceptible of atmospherical and electrical changes, and on a sudden alteration 

 of the weather we have known them perish by myriads in a night. The con- 

 dition of a plant is never hopeless, however severe the attack may be, pro- 

 vided there is time for it to put forth its lateral or fructifying branches." 



The progress and termination of the attack by the lice, when severe, is thus 

 described in the same work. 



"Their multiplication is so rapid that the leaves become so thickly covered as 

 scarcely to allow a pin to be thrust between them. They quickly abstract the 

 juices of the bine, so that the leaves assume a sickly brown hue, and curl up, 

 and the bine itself ceases to grow, and falls from the pole, the lice continuing 

 till they perish for want of food ; and thus, Avithout the intervention of a favor- 

 able change, the crop is destroyed, and the grower may often consider himself 

 fortunate if the plant recover a due amount of vitality to produce a crop in the 

 following year. 



" When atmospherical change occurs, the lice die off by thousands in a day. 

 As they die they turn a brown color. The first indication of a favorable change 

 is the clustering of the lice to the extremities of the bines and branches. This 

 fact is well worthy of notice, since, to all but close and accurate observers of 

 the hop plant, the outward appearance is the reverse of a favorable change ; 

 for the small leaves and heads of the bines are densely covered with lice. But 

 while the lice are thus gathering in countless myriads at the extremities, ap- 

 parently threatening the utter destruction of the plant, the large leaves at the 

 bottom of the bine and the leaves of the branches next the stem are becoming 

 clean. At this clustering period the lice evidently cease to suck the jnices of 

 the plant ; for the attentive observer will perceive the bine resuming its erect 

 position, and recommencing its upward growth, though still covered with lice. 

 At this crisis they usually disappear altogether in the course of a week or ten 

 days, and then the plants should be liberally rewarded, if not lavishly stimu- 

 lated with manure, there being no danger of over-manuring under such circum- 

 stances. 



"The best manure to be employed in these cases is guano, at the rate of 450 

 to 900 pounds per acre. The ground should be continually stirreil, but this 

 stimulus should not be given until it is certain the lice are disappearing." 



Injurious insects are much lessened in number by natural enemies. That 

 which is most destructive of these lice is tlie lady-bug, or, as called iu England, 

 the lady-bird. Of these the Avork just quoted from says : 



"They, in the first instance, destroy multitudes of lice, a single one killing 

 eight or ten in as many minutes ; and where the lice are not too numerous, the 

 lady-birds will clean the hop plantations. But, generally, the lice have time to 

 deposit some of their young on the under side of the leaves before their enemies 

 attack them, especially if the weather be clouded, when the lady-birds are slug- 



