. Circular. Insect pests; Insect pests. 5 Northern States and westward to the Mississippi, and has yet, during all this time, rarely been reported as injuriously abundant, argues that the conditions favorable to its increase are seldom met with. Its complete disappearance in one orchard, after a year of excessive abundance, is a case in point ; and the excessive multiplication in New York State in L89] was followed the next year, according to .Mr. Slingerland, by scarcely any injury in comparison. The reasons for the sudden multiplication and quite as sudden disappearance of this pest are diff
. Circular. Insect pests; Insect pests. 5 Northern States and westward to the Mississippi, and has yet, during all this time, rarely been reported as injuriously abundant, argues that the conditions favorable to its increase are seldom met with. Its complete disappearance in one orchard, after a year of excessive abundance, is a case in point ; and the excessive multiplication in New York State in L89] was followed the next year, according to .Mr. Slingerland, by scarcely any injury in comparison. The reasons for the sudden multiplication and quite as sudden disappearance of this pest are difficult to give. A succession of two or three winters favorable to hibernation probably leads to the unusual increase, and the resulting attack brings the trees into a condition which is probably prejudicial to the insect. With the later summer broods, as pointed out above, the condition of the leaves which have been seriously attacked by the earlier broods is such that the insect becomes markedly less abundant later in the season. The green, succulent foliage of the. Fio. i.âChrysopa oculata Say : a. eggs; 6, Eull-grown larva : .â . foot of same: </. same devouring a I'sylla ; /', cocoon; f, adult insect : g, head of same; h. adult, natural sizeâall enlarged except h ioriginal). young spring growth is especially favorable, and when the leaves become haidened and mature, and especially dry and innutritions, from having been already sapped of their vitality, they are distasteful and unsuited to the develop- ment of the later hi' Is. The parasitic and predaceous insects also become very efficacious by mid- summer, and a very interesting experience in the case of the Maryland invasion will be now noted. NATURAL ENEMIES. No enemy for this insect among the parasitic and predaceous species has, previous to this year, been recorded. n my first visit to the Maryland orchard I was shown what was taken to be the egg of the I'sylla, which proved, however, to he the egg of a common lac
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