2 BULLETIN 107, U. S. DEPARTMENT OF AGRICULTURE. 



Utah, east to Evanston, Almy, and Lyman, Wyo., and northeast to 

 Cokeville, Wyo., Randolph and Laketown, Utah, and Fish Haven, 

 Idaho. 1 



An insect must become fairly common before it can form an appre- 

 ciable portion of the food of birds; in most of the area covered by 

 the writer's investigations the weevil probably had not become 

 abundant until 1907 or 1908, and doubtless had not attracted the 

 attention of birds much before that time. Thus any preference 

 shown by birds for this character of food was necessarily acquired 

 in the short period of four or five years. 



LIFE HISTORY OF THE WEEVIL. 2 



The alfalfa weevil is a small snout beetle a little less than one- 

 fourth inch in length, and when it appears in spring its color is 

 very dark brown or black. It passes the winter in the adult stage, 

 protected under piles of rubbish, in vegetation along ditch banks, 

 the base of haystacks, etc. The beetles soon become active, and on 

 fair, warm days may be found flying, sometimes in considerable 

 numbers, when some fall prey to the earlier arrivals among the 

 flycatchers and swallows. At this time of year the numbers are at 

 the lowest ebb, since comparatively few survive the rigors of winter 

 and live to perpetuate the race. 



The seasonal activities of the insect are influenced strongly by 

 temperature. In normal years many eggs are laid by the first of 

 April and the bulk before the middle of June, but the process may 

 continue as late as July. 



From 10 to 12 days elapse before hatching. The pale, newly 

 hatched larvae soon work their way to the tender leaves and growing 

 buds at the top of stalks, where for some time they may easily escape 

 the notice even of birds, being of such minute size and confining 

 their early feeding to the inner folds of the leaves. At first the 

 larvse restrict their depredations to the more succulent portions of 

 the foliage, but by the time they have become full sized they feed 

 anywhere upon the plant where green leaves remain. 



The larvse become full-grown in from 20 to 60 days, and during 

 this time they pass through three stages. When fully developed 

 they are about one- fourth of an inch long, of a bright green color, 

 and have a conspicuous white stripe down the back. A paler stripe 

 on each side and the black head aid in distinguishing it from other 

 larvse. 



1 Webster, F. M., Bull. 112, Bu. of Entomology, IT. S. Dept. of Agr., May, 1912. 



2 The entomological data here given are from Bull. 112 of the Bu. of Entomology, 

 U. S. Dept. of Agr., by F. M. Webster, and Bull. 110, Utah Agr. Coll. Exp. Sta., by E. G. 

 Titus. 



