284 INSECTS AFFECTING VEGETATION 



in drops. In July winged individuals appear in the colony and 

 soon after they fly away to some unknown plant. The remainder 

 of the summer is spent away from the elm, until the remarkable 

 migration of autumn recalls the pest. 



Eight infested elms were sprayed experimentally at Pullman. 

 As a result the insect was checked, but in no case was it completely 

 exterminated. The sulphur-lime wash gave the best satisfaction. 

 It is recommended that trees infested with the leaf-louse be sprayed 

 during the winter with the sulphur-lime wash before the buds burst 

 in the spring. Attention should be given to the innermost crevices 

 of the trunk and larger branches as it is in such places that the eggs 

 are most apt to withstand the rigors of winter. The sulphur-lime 

 wash is a slow poison. Its effectiveness continues for many weeks 

 after its application. 



From this outline of the life history it will appear that the 

 leaf-louse does not live over from year to year on the elm, but that 

 trees become infested only by the autumnal migration. Should 

 the winter spray of sulphur-lime not be given, as is sometimes un- 

 avoidable, owing to the proximity of painted buildings, it will be 

 necessary to spray with kerosene emulsion as soon as the trees are 

 in leaf, and before the leaves start to curl. After the leaves have 

 curled it is impossible to reach the louse. Trees affected year after 

 year become dwarfed and stunted, and are entirely valueless as 

 ornamental shade trees. (Bui. 74, Wash. E. S.) 



The Boxelder Plant-Bug. This is a plant-bug found through- 

 out the summer on boxelder. When full grown, it is nearly half an 

 inch in length, of a dark gray color, and marked with red. In its 

 earlier stages the red predominates, that being the color of the 

 exposed body. It breeds frequently in enormous numbers upon 

 the boxelder, becoming more numerous in the autumn than at 

 other seasons. The bugs congregate in groups upon the trunks of 

 these trees, and migrate in search of hibernating quarters to fences 

 and the sides of houses, frequently entering houses and other build- 

 ings and stowing themselves away for the winter in protected places. 

 They suck the juices of the leaves and more tender growth of the 

 boxelder tree, and have been reported as damaging fruit, such as 

 peaches, plums, and apples. (Cir. 28, Second Series U. S. D. A., 

 B. E.) 



In 1880 the insect was known from Colorado, Arizona, Cali- 

 fornia, Kansas, Missouri, Utah, and Mexico. Prof. E. A. Popenoe, 

 writing in 1880, recorded its abundance upon boxelder at Man- 

 hattan, Kans. Dr. J. A. Lintner, in 1887, showed that it had not 

 been recorded west of the Mississippi River or north of Missouri. 

 In 1881, however, it had been received at this office from Sioux 

 City, Iowa, from Mr. D. H. Talbot, who, writing under date of 

 November 2, 1881, stated that it was very numerous that autumn. 



During the winter the adult insect hibernates in all sorts of 

 sheltered localities. It is especially abundant in fences, crevices of 

 stone walls, and in the angles of stone buildings, on the south side 

 of which it is reported to appear singly and in clusters upon every 



