December, '10] TITUS: ALFALFA LEAF-WEEVIL 459 



ON THE LIFE HISTORY OF THE ALFALFA LEAF-WEEVIL 



By E. G. Titus, Logan, Utah 



The alfalfa leaf-weevil {Phytonomus murinus Fab.) now occurs in 

 at least eight counties in Utah. * 



In 1908 the distribution was probably limited to 100 square miles 

 in Salt Lake and Summit counties. It now covers an area eighty 

 miles long, north and south, by seventy-five miles east and west or a 

 gain in 1909 and 1910 equal to sixty times the previously infested area. 



The present known infested area covers all of Salt Lake and Davis 

 counties, north half of Utah county, southern part of Weber, north- 

 eastern Tooele, northwestern Wasatch, eastern Summit and the 

 south half of Morgan county. 



Specimens have been taken from trains passing thru Box Elder and 

 Cache counties, these two counties forming part of the north bound- 

 ary of the state. It is not unlikely that there are isolated colonies 

 breeding in these and other counties. In Summit county it has 

 nearly or quite reached the Wyoming line. 



There are so many means of distribution, such as the spring and 

 summer flights, railroad and wagon road transportation, carriage in 

 fruit packages, household goods and other packages, that it is cer- 

 tainly a question of but a short time before the species will be present 

 in other states. 



Food Plants 



It has been found feeding and breeding on seven species represent- 

 ing three genera of plants: alfalfa {Medicago sativa), burr-clover 

 {M. lupulina), white sweet clover (Melilotus alba), yellow sweet clover 

 (M. officinalis), red clover {Trifoliuvi pratense), white clover (T. 

 repens), alsike clover (7", hyhridum) and crimson clover (7". incar- 

 natum). 



Several species of clovers have been described from the Rocky 

 Mountain region but these seem to be rather rare and so far the weevil 

 has not been found attacking them. 



The wild sweet pea (Lathyrus venosus) is not uncommon thruout 

 the state, but even where growing beside infested alfalfa plants it 

 has not been attacked. 



Failure has resulted from attempts to breed the weevils in captiv- 

 ity on hairy vetch (Vicia villosa) and buffalo pea (Astragalus utahen- 

 sis). Adults are often found hibernating beneath the leaves of this 

 latter plant and in captivity would occasionally eat small pieces from 

 the leaves. 



