60 ENTOMOLOGICAL SOCIETY OF ONTARIO. 



The appearance of the GrainAphis, Siphonnphoj'a avenae, in such enormous numbers, 

 during some seasons and the almost total absence of them during others, are matters of 

 continued observatiouj but the causes therefor are not well understood. The present 

 season, there was, quite early, indication of an outbreak of this species, but later it 

 largely disappeared, while the cause for its doing so is obscure. Now, with all the light 

 on the subject that I have been able to gain from several years' study of this insect, I am 

 about convinced that the secret lies in the condition of the weather during spring ; that 



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Fig. 41. ^$ -. ^\ 



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Fig. 42. Fig. 43 



cold, wet weather, at that season retards the development of their Hymenopterous para.- 

 sites, by which they are largely held in check, but does not retard their own development 

 to the same extent, thus giving them an advantage, early in the season, which is some- 

 times not overcome until much later and after the aphis has worked some injury. One 

 other observation and I am done, though if space would allow, and time permitted me ta 

 go over my note books, I could multiply the number by at least tifty. 



Late in April and early in May of the present year, there was considerable con- 

 sternation among the farmers over a large portion of the State of Ohio, caused by the 

 appearance of enormous numbers of the larva? of the Clover Leaf Weevil, F/ii/tono)mis 

 punctatus, in the clover fields. These larv;i? were literally swarming and eating the plants to 

 the ground, which, together with the drouth prevailing at the time over the northern 

 portion of the State, gave matters anything but a favorable appearance, and it seemed 

 that many fields could not escape ruin. In fact, an occasional farmer was frightened into 

 plowing up his fields. But just here a fungous disease, Entomophthora sphaerospermtiy 

 Fresn., appeared and the effect was astounding. Farmers who had about given up all 

 hope of a hay crop, wrote to say that the worms were all dead or dying and they could 

 not find a live one. One farmer, who came in to consult me about breaking up his field, 

 came a few days later to say that all the worms were dead or dying, and I found a close 

 search was necessary to fine a healthy one of any size, and but few of even the youngest. 

 Now, I do not believe a million dollars would cover the saving to the hay crop of Ohio, 

 by this minute fungus, the present year. But this is not all. Soon after, rains occurred 

 and the eliect of the worms resulted only in retarding the blooming of the clover, pre- 

 cisely the efiect of mowing or pasturing when done to prevent the depredations of the 

 Olover-seed Midge, Cecidomyia leguminicola, and whether the result was the same or not, 

 the farmers over the area covered by this Leaf Weevil, harvested a good crop of clover 

 seed. 



