252 Forty-second Report on the State Museum. [110] 



probably in the same way that it does from the winter wheat to the 

 spring wheat and oats in the spring, that is, by the winged individuals. 

 Here they work upon the leaves and stalks singly while the weather 

 is not too cold, but when winter appears they move downward toward 

 the ground, some of them, at least, entering the soil and feeding on 

 the sap of the roots. At any rate, I find the apterous ones at this 

 time working upon the roots, but at the same time I find a winged 

 individual above ground.* I have observed them heretofore at the root 

 of the wheat late in the winter, while snow was on the ground, and, 

 what somewhat surprised me, I found them busy at work under the 

 snow, and the apterous females bearing well-formed larvse. I am, 

 therefore, led to believe that in this latitude the sj)ecies passes the 

 winter in other than the egg state. This will probably be found true 

 wherever winter wheat is grown." 



The above will serve to show how much yet remains to be learned 

 of the life-history of this species. A male unknown and no knowledge 

 of an egg-laying female, should be a sufficient stimulus for its further 

 stud}'. Dr. Pitch has written of it : "I have watched the grain aphis 

 this year [1862] round so closely that I am perfectly assured 

 that no eggs were laid and no males were produ^ced. When and 

 under what circumstances males occur, if they ever do occur, is yet 

 remaining to be discovered. At present it seems as if these insects 

 might go on forever producing young without any intercourse of the 

 sexes." 



Is it possible that this sjjecies will be found to confirm a statement 

 made by Kyber, a careful and skillful student of the Aphididai, that 

 certain species that feed on herbaceous plants which fruit early in the 

 year and then wither, produce males and apterous oviparous females 

 in the middle of the summer? 



• Its Food-plants. 



The grain aphis is by no means confined to wheat, barley, and oats. 

 Kaltenbach has enumerated as its food-plants Secale cereale (rye), 

 Triticum sativum, Avena fatua, Hordeum niurinumi, Bromus mollis (soft 

 chess), Dactylis glomer'ata (orchard-grass), Holcus and Poa. Walker 

 has added Glyceria jiuitans and Polygonum persicaria. Passerini 

 records it on various species of sorghum in Europe, including Sorghum 

 saccharinum. Mr. Oestlund has found it in Minnesota, on Phalai'is 

 canariensis (canary-grass) and on Poa annua. 



*See, in this connection, a statement made to Mr. Glover, which would seem to indi- 

 cate an unusual degree of endurance of cold (although doubtless not to the extent 

 reported), viz., that " they freeze on the stalks in winter and revive in the spring." 



