April, '15] 



GLENN: APPLE FLEA-WEEVIL 



281 



leaf on the tree contains one or more. The beetles in feeding work on 

 the under sides of the leaves and eat out the soft tissues between the 

 veinlets, leaving the epidermis of the upper surface of the leaf unin- 

 jured. The pits thus made b^^ them are from one-half to one milli- 

 meter in diameter, and a num.ber of them are usually made together, 

 being separated only by the veinlets, which are left uninjured. Badly 

 injured leaves present a sieve-like appearance when viewed from be- 

 neath. A single beetle confined for several days on fresh leaves made 

 an average of nine such feeding-pits a day. Since the number of 

 beetles on a tree frequently equals the number of leaves, it will readily 

 be seen that they are capable of becoming a very serious pest. The 

 injury, however, is usually not very serious, but varies greatly in 

 different localities and in different seasons. The reduction of leaf 

 surface caused by the beetles varies from a fraction of 1 per cent to 

 50 per cent or more, of the entire leaf surface. A reduction of 50, or 

 even 25 per cent of the leaf surface in this way is a very serious in- 

 jury, since it not only deprives the tree of a large per cent of its food 

 elaborating tissues, but the removal of the epidermis of the lower sur- 

 face in so many places exposes the soft tissues of the leaf to the drying 

 effects of the atmosphere, and to the injurious action of spray mix- 

 tures, and opens the way for the entrance of the spores of injurious 

 fungous diseases, resulting usually in the total loss of badly infested 

 leaves. 



/ Life-History and Habits 



The insect is single-brooded. The winter is passed by the adult 

 among leaves and grass and under clods or in cracks in the ground, 

 under and near trees which they infest in orchards or woodlands. 

 These hibernating adults become active in spring as soon as the frost 

 is out of the ground, or about the last week in March in the latitude of 

 St. Louis; and ascend to the branches, there to await the appearance 

 of the leaves. As soon as the leaves appear they begin to feed on them, 

 and by the middle of April or a little later, begin to deposit eggs. The 

 eggs are deposited in the large veins of the leaves, in longitudinal 

 cavities gnawed out from the under side by the female. Egg-laying 

 continues for about a month, or to about the middle of May, after 

 which time the adults soon die. The egg hatches in four or five days 

 and the larva as it feeds constructs a mine extending toward the edge 

 and usually towards the tip of the leaf. When the edge of the leaf 

 is reached the mine becomes a blotch-mine. The larva matures in 

 about three weeks and constructs within the mine a sort of cocoon, 

 within which it pupates, and from which a few days later the adult 

 beetle emerges. These mines when fully developed are brick red in 

 color and are quite conspicuous. As a result of the wound made by 



