264 Lawson on Aphis Avence, 



ARTICLE XXV. — On Aphis Avence^ By George Lawsow, 



Ph., D., LL.D. 



(^For the Canadian Naturalist). 



In my Report an the Insects affecting the Field Crops, &c., in 

 Canada, during the season of 1861, notice was taken of the sud- 

 den appearance of the Wheat or Grain Aphis (not found to b© 

 identical with the Aphis Avenoe of Europe,) in alarming numbers 

 on Wheat, Oats, Rye, &c. During the present season (1862) the 

 insect has played over again the part which it took in 1861^ and 

 which created so much alarm among our farmers. They are 

 better acquainted with the stranger now, knowing that he comes 

 merely to suck the green juicy grain without the means of doing 

 much mischief; but, having obviously become a permanent co- 

 lonist, it is desirable that a few facts connected with his first ap- 

 pearance and settlement in our country should be placed on re- 

 cord in the Canadian Naturalist. 



In the beginning of August, 1861, ears of wheat infested with 

 this insect were transmitted to me by several farmers and others 

 in the neighbourhood of Kingston, all of whom regarded the in- 

 sect as a new pest to the country. The earliest examples were 

 received from Professor Williamson, Portsmouth, John Duff, 

 Esq., Princess Street, A. Drummond, Esq., Manager of the Mon- 

 treal Bank, Messrs. Piatt, Napanee, and from farmers in the neigh- 

 bourhood of Odessa, and in Pittsburg. A few days afterwards 

 reports were found in the newspapers of its appearance in various 

 parts of Upper and Lower Canada, and over a considerable por- 

 tion of the Northern States ; all reports spoke of the insect as 

 new and unknown to the farmers. More special enquiry among 

 entomological friends and reference to published works, only ser- 

 ved to confirm the surmise that there existed no record or tradi- 

 tion of its previous occurrence in our fields. Prof. Williamson, 

 who had for many years observed with care the insects affecting 

 the crops in this locality, had not previously seen this species of 

 Aphis on any of the grains ; numerous farmers of whom enquiries 

 were made in different parts of the country knew nothing of the 

 insect in former years. And, lastly. Dr. Asa Fitch, the able en- 

 tomologist to the State of New York, whose keen eye has added 

 so much to our knowledge of economic entomology, recognised 

 in the Aphis a new vagabond whose photograph and antecedents 

 required to be reported to the State authorities. 



The insect is individually minute, like all the Aphides, but pre- 



