THE CANADIAN ENTOMOLOGIST 71 



ranean attacks of the larva^ of this species on the roots of alfalfa. 

 Thus, within five years, this insect has advanced from one of 

 apparently little or no economic importance, to one of the pests of 

 the alfalfa field that must be reckoned with by alfalfa growers in 

 future. 



In 1909 Mr. Hyslop, in his entomological investigations about 

 Pullman, Washington, found that the larvae of the moth Autographa 

 gamma calif ornica attacked alfalfa plants, but these injuries were 

 encountered so rarely that there did not appear to be any good 

 reason for paying any special attention to the species. It was, 

 however, convenient to carry on the observations, and in doing 

 this' Mr. Hyslop became impressed with the possibility that, in 

 the event of its natural enemies becoming so reduced as to be 

 unable to hold the species in check, it might become an insect of 

 much more economic importance than his observations at that 

 time would indicate. But, here again, it was difficult to explain, 

 clearly, the necessity for the expenditures of time and funds re- 

 quired to carry out the investigation of the species, or to ask for 

 the publication of the results. During the summer of 1914 the 

 very conditions that it was thought might possibly come to pre- 

 vail, did actually develop. Something transpired to prevept the 

 development of the natural enemies of Autographa, in sufficient 

 numbers to keep the pest in check, and as a result, throughout a 

 number of the northwestern States, the species became a veritable 

 scourge, and many letters were received complaining of its ravages. 



In June, 1884, Toxoptera graminum, now better known as the 

 notorious green bug, was introduced into a breeding cage in northern 

 Indiana, where the writer was temporarily located. Up to that 

 time the species was not known to occur in America excepting at 

 one point. Cabin John Bridge, Maryland, a few miles north of 

 Washington; and while, as later examination of the old records 

 show, that the species had probably been injurious in Virginia two 

 years prior to that date, at the time of the accidental introduction 

 into the writer's breeding cages, it was not known as a destructive 

 insect at all, and therefore the investigation made at that time was 

 barely warranted by its then economic importance. Since that 

 time it has come to be one of the most destructive pests of the 

 grain field, and is probably more dreaded by the grain growers of 



