NOTES AND ABSTRACTS. 



245 



that the action of the poison in dilute solutions is masked by the 

 presence of the nutrient salts, which thus enable plants when grown 

 in such solutions as water-cultures to endure to a much greater con- 

 centration of the toxic substance than in the absence of nutrients. 

 Copper sulphate, a definite poison to barley, does not have any stimu- 

 lative effect in very dilute solutions, even at so low a concentration as 

 one in ten million. 



The experiments with manganese sulphate showed that this sub- 

 stance, though not an actual toxic to barley, retards its growth con- 

 siderably if supplied in moderate quantities. Very minute quantities 

 have a decidedly stimulative action both on the root and shoot. 



A. D. C. 



Corn, Experiments with. By E. G. Montgomery {U.S.A. Exp. 

 Stn., Nehraska, Bull. 112; December 1909; plates). — An account of 

 six years' work in selecting, breeding, and experimental cultivation 

 of Indian corn in Nebraska. The results so far show that : 



1. A long type of ear is best. 



2. The size of ear depends on environment and is only of import- 

 ance when it is known under what conditions the plant was grown. 



3. A medium depth of kennel is to be preferred. 



4. Low ears give as good yield and mature earlier. 



5. Large or small stalks do not yield as well as stalks just above the 

 medium in size. 



6. The amount of leaf does not seem to be related to yield. 



7. Strains capable of producing ear-bearing tillers or suckers yield 

 best. 



8. Barren plants decrease yield. — M. L. H. 



Corn Root-Aphis, Contributions to a Knowledg-e of. By 



E. A. Vickery (U.S.A. Dep. Agr. Bur. Entom., Bull. 85; part vi. ; 

 July 12, 1910; 6 figs., 1 plate). — The corn root-aphis [Aphis maidi- 

 radicis Forbes) is one of the many insects that infest the corn plant. 

 Among its other food-plants are pumpkin, squash, strawberries, culti- 

 vated asters, and probably dahlias and French artichokes. It was first 

 noted by Walsh in 1862 and has recived considerable attention since 

 from economic entomologists. In Illinois the eggs are found hatching 

 in the fields from April 8 to May 22, and from ten to twenty-two genera- 

 tions may follow. Sexual forms are produced in the latter part of 

 September and October, and eggs are laid in October and November 

 but do not hatch until the following spring. There is a form which 

 feeds on fleabanes (Erigeron) and on wild asters, described by Cyrus 

 Thomas in 1879 as Aphis middletoni. This is probably a distinct 

 species, although further study may show that it is the same as Aphis 

 maidi-radicis , in which case both forms would be known as Aphis 

 middletoni Thos. — V . G. J. 

 ♦ 



Corn Stalk-Borer, The Larg'er {Viatraea saccharaUs Fab.) By 

 George G. Ainslie {U.S.A. Dep. Agr. Bur. Entom., Circ. 116;Eevision 



