240 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 4 



The Manitoba beetles are considerably later in making their appear- 

 ance than farther east and south. Here the first are generally noticed 

 about June 15, at the time when potatoes are just making their way 

 through the ground. In 1910 the first larvae. were observed June 13, 

 and these reached the adult state July 16, and became sexually mature 

 towards the end of the month. On August 8 some of these commenced 

 depositing eggs and larvse were noted a few days later. A few of these 

 pupated the second week in September, but no beetles appeared from 

 them, and their condition late in October left little doubt that most^ 

 if not all, of them would perish during the winter. 



Successive applications of Paris green proved perfectly satisfactory. 



There was also a remarkable outbreak of June beetles, in the larval 

 state. One species — Lachnosterna fusca — was so plentiful that it 

 caused the total destruction of large patches of native grasses, in some 

 instances covering an area of half an acre or more. These were well 

 up on the grass land, while another species did some injury to potatoes 

 in moist situations. 



Trees and shrubs also suffered from the ravages of several 

 insects during the year, of which the following were the most 

 important : 



The Willow-leaf Beetle, GaleruceUa decora. — Overwintering beetles 

 appeared in swarms as soon as willows commenced to form leaves and 

 in the course of a month had almost defoliated most of these shrubs, 

 after which they vanished, being very severely attacked by a red mite 

 and doubtless by other parasites. 



This beetle appears every few years and occasionjilly is the cause of 

 much injury to aspen poplars (P. tremuloides) , apart from completely 

 skeletonizing several species of willow. The chief damage to aspens 

 is when they commence to leaf out before the willows or later in the 

 season when the latter, through defoliation, are no longer available 

 for food. The larvae seem to be entirely confined to species of Salix. 

 There is but one brood in a season. 



The Aspen-poplar-leaf Beetle, Lina tremulce. — This is another pest 

 that kills many young trees every eight or ten years, besides making 

 aspen bluffs almost uninhabitable at certain seasons, owing to the 

 very disagreeable odor of the larvae. The species is gradually increasing 

 and may be expected to become very injurious again within the next 

 two years. 



Pepper-grass Beetle yGaleruca externa, — Were in very large numbers 

 in places where their favorite food plant (Lepidium) was prevalent^ 

 and in consequence did much good. Years when this plant fails 

 however, they are apt to attack other cruciferous plants and have 

 been known to extensively injure young turnip and cabbage plants. 



