April, '14] GIBSON: POROSAGROTIS INJURIES 201 



A NEW DESTRUCTIVE CUTWORM OF THE GENUS POROSA- 

 GROTIS, OCCURRING IN WESTERN CANADA 



By Arthur Gibson, Chief Assistant Entomologist, Division of Entomology, 



Ottawa, Canada 



111 June, 1911, reports reached the Division, from southern Alberta 

 of extensive injury to grain crops owing to the ravages of cutworms. 

 From material received two moths were reared which were determined 

 at the time by Mr. F. H. Wolley-Dod as Porosagrotis delorata Sm. A 

 brief record of one instance where a correspondent claimed to have lost 

 320 acres of wheat, before June 21, was referred to in my bulletin on 

 cutworms (No. 3, Dominion of Canada, Division of Entomology, 

 Frebuary, 1912), and Dr. C. Gordon Hewitt also referred to the out- 

 break in his annual report, as Dominion Entomologist, for the year 

 ending March 31, 1912. This was the first occurrence on record of this 

 cutworm as an injurious species; in fact, the insect had hitherto been 

 looked upon as an extreme rarity in Canada. 



During the first half of May, 1912, farmers in the neighborhood of 

 Lethbridge, Monarch, McLeod, and other places in southern Alberta, 

 noticed large numbers of the cutworms in their fields. Mr. W. H. 

 Fairfield, superintendent of the Experimental Station at Lethbridge, 

 reported that the first noticeable damage to crops was on May 6. A 

 correspondent at McLeod, Alberta, 32 miles from Lethbridge, stated 

 that the cutworms began to attack fall wheat about the middle of 

 April. Other crops destroyed were spring wheat, when it came up 

 about the beginning of May, oats, barley, beets, onions, cabbages, 

 carrots, etc. Many acres which were in spring wheat, and which 

 had been destroyed later, were sown to oats in early June, and 

 this crop wag also completely eaten. In some instances as many 

 as three sowings were made. In the Lethbridge Land District, from 

 the city of Lethbridge westward to Pearce, and northward taking in 

 Diamond City, Monarch, Stanton and other immediate settlements, 

 it has been carefully estimated that actually 33 per cent, of the grain 

 sown was destroyed. From personal visits made to infested districts 

 Mr. Fairfield stated that he was of the opinion that between 30,000 

 and 35,000 acres of grain had actually been destroyed by cutworms, 

 in 1912, in the southern part of the Province of Alberta. 



On May 10, 1912, larvse collected at Lethbridge on May 6, were 

 received at Ottawa. These w^ere of different sizes from about half an 

 inch to one inch in length. Some of these larvse were full grown and 

 entered the earth for pupation on May 28. The larvse remained in the 

 earth, no change taking place until June 18, when the first pupa was 



