June, '12] CRIDDLE: INSECTS OF MANITOBA 251 



of attention. Considerable injury was clone by it to potatoes, and 

 several garden plants were attacked, including Nicandra physaloides 

 and Nicotiana affinis. 



Turnip Beetle, Entomoscelis adonidis. — Very prevalent in June upon 

 small wallflower. Erysimum parviflorum, which is its native food plant. 

 Later it became quite rare and was only present in small numbers 

 upon turnips in the fall. 



Peppergrass Beetle, Galeruca externa. — This insect was enormously 

 abundant wherever its chief food plant occurred. During May larvsB 

 were found covering the ground in patches of several feet in circum- 

 ference and plants of Lepidiian were so badly infested that in places 

 where they prevailed to the exclusion of other plants, large patches 

 of half an acre or more were completely stripped bare and killed. 

 Besides these all other species of Criiciferce were attacked especially 

 the genus Arabis, but farm crops escaped with slight injury due no 

 doubt, to their scarcity in the family of plants usually eaten. 



Miscellaneous 



Among insects not so directly affecting agriculture, that were com- 

 mon during the year, the following are worthy of being recorded: 



Willow-leaf Beetle. Galerucella decora. — This beetle appeared sud- 

 denly on the 31st of May from unknown breeding grounds and at 

 once proceeded to attack Aspen poplars which by the evening in 

 certain spots, were actually bent down with the weight of beetles upon 

 them and from a short distance whole bushes had a spotty grey appear- 

 ance. The insects seemed to have congregated in certain places so 

 that every tree covering an area of several acres would be infested, 

 while the surrounding country remained comparatively free, edges of 

 bushes were more attacked than centers and the sunny sides more so 

 than shady ones. 



Within twenty-four hours most of the leaves within the infested 

 areas had been skeletonized, causing them to shrivel up and turn a 

 dirty bro^^Ti color. Willows also suffered severely, eventually more so 

 than the poplars because it is upon them that the insects breed. This 

 became abundantly manifest later in the season when the willows 

 becoming completely stripped many of the larvae died from starvation 

 and but a moderate proportion reached maturity. 



June Beetles Lachnosterna sp. including rugosa, dubia and grandis 

 as determined by Doctor Glasgow, did considerable injury by eating 

 the leaves of several trees and shrubs, but the larvae were less numerous 

 than usual and so caused little trouble. 



Another leaf eater observed here for the first time was the Larch 

 Sawfly. Though from the fact that even isolated trees, far removed 



