NOTES AND ABSTEACTS. 



235 



Coral Spot Fung-us {Gnrden, Oct. 2, 1909, p. 485).— This is 

 the well-known fungus found on dead wood. When the spores first 

 germinate they are incapable of attacking living tissue, and can only 

 grow on dead wood ; but when once it has gained an entrance to dead 

 wood the mycelium will spread to and kill adjacent living tissue. It 

 is therefore well to keep the fungus in check, and not leave dead wood 

 lying about where it may do harm. — H. R. D. 



Cornfield Ant, Lasius nig'er americanus, Habits and Be- 

 haviour of. By S. A. Forbes (U.S.A. Exp. Stn. Illinois, Bull. 131 ; 

 Dec. 1908 ; 1 plate). — This ant, which is nearly related to a common 

 British species, does harm in maize fields in two ways — directly in 

 some seasons by hollowing out seeds, and so either killing them or 

 reducing the amount of reserve food at the disposal of the young plants ; 

 and indirectly by keeping aphides which prey on the roots of the plants. 

 It is shown that a change of crop, from maize to some other upon 

 which the aphides do not feed, is followed by a migration of the ants, 

 provided weeds are kept dowm. Numerous notes on life-history, etc., 

 are given. — F. J. G. 



Corn-root Aphis, Experiments with Repellents agrainst. 



By S. A. Forbes {U.S.A. Exp. Stn. Illinois, Bull 130; Dec. 1908).— 

 The experiments detailed were carried out in 1905 and 1906, and, 

 while not conclusive, show the possibilities of using repellents with 

 success. The only natural agency checking this pest, which is closely 

 connected with the cornfield ant, is a long-continued soaking of the 

 ground by frequent heavy rains, especially in the spring. A test was 

 carried out with a large number of substances possibly useful for the 

 purpose, to ascertain their infiuence upon the germination and subse- 

 quent growth of the plants. Four were selected, and the seeds treated 

 therewith before using— viz. oil of lemon, carboHc acid, formalin, and 

 kerosene, and all in the order named insured a larger yield than the 

 untreated seeds. The author considers, however, that much larger 

 numbers of experiments are necessary. Eotation, thorough cultivation, 

 and proper manuring, as well as the use of repellents, are the methods 

 to be adopted in dealing with this pest. — F. J. G. 



Cotton, Eg-yptian, A Study of Diversity in. By 0. F. Cook, 

 Argyle McLachlan, and Eowland M. Meade [U.S.A. Dep. Agr., Bur. 

 PL Ind., Bull. 156; 6 plates). — The diversity shown in introduced 

 Egyptian Cottons is divided into four classes: — 



(a) Owing to insect cross fertilization. 



(b) Owing to incomplete acclimatization. 



(c) Differences in physical environment. 



^ {d) Differences existing in the same individual. 



A detailed description of the three varieties imported — viz. Janno- 

 vitch, Mit Afifi, and Dale — is given, and it is evident that neither of 

 these is a pure strain 



