SOME DESTRUCTIVE SCALE INSECTS OF NEW YORK 269 



SOME DESTRUCTIYE SCALE-INSECTS OF THE STATE 

 OF NEW YORK 



Before proceeding to the consideration of the San Jose scale, — 

 the subject of this bulletin, it may be of service to refer briefly to a 

 few other species which, although common in the State of New 

 York, and quite harmful to the trees that they infest, are still 

 almost wholly unknown to the fruit-grower and to others who are 

 suffering from their presence. From the figures given of them, 

 they may at once be distinguished from the San Jose scale. 



The Apple-tube Bark-louse 



The most common of these is the apple-tree bark-louse, shown in 

 Fig. 1 of Plate I, in its natural size as it occurs on the bark of 

 trunks and limbs, often more abundantly than is represented in the 

 cut, completely covering the bark and overlaying one another, and 

 lending an increased diameter to the infested twig. The color of 

 the scale is brown or ash-gray, nearly approaching that of the bark. 

 The female scale measures about one-twelfth of an inch in length, 

 of a long, usually more or less curved form, pointed at one end on 

 which a magnifier may show the yellowish cast-off skin of the insect, 

 and rounded at the othar end. From its peculiar shape it has been 

 frequently written of under the name of the oyster-shell bark-louse. 

 It bears the scientific name of Mytilaspis jpomorum Bouche. The 

 male scale is of a considerably smaller size, the sides nearly straight, 

 less rounded at the larger end, and of a brighter color. It will sel- 

 dom be found associated with the females on the bark, as its natural 

 place is on the leaves on either side, especially along the midrib 

 (Riley). If a recent uninjured female scale be carefully lifted after 

 oviposition — at any time during the winter — from fifty to a hun- 

 dred small, oval, white eggs may be found underneath it, which, 

 would ordinarily give out the young insect about the first of June 

 in the latitude of New York. 



This destructive scale is far from being confined to the apple, but 

 may also be found on the plum, pear, raspberry, wild gooseberry, 

 wild cherry, red currant, sugar and swamp maples, white and black 

 ash, birch, poplar, willows, linden, horse chestnut, elm, &c. It will 

 be seen from the above, that it has a large number of host-plants. 



