992 EXPERIMENT STATION RECORD. 



hydrocyanic-acid gas. In the ordinary greenhouse 7 mg. of potassium cyanid is 

 sufficient for each cuhic foot of space. It is recommended that fumigation be done 

 at night, when the foliage is dry. If it is undesirable to use hydrocyanic-acid gas the 

 greenhouses may be fumigated with tobacco, or whale-oil soap may be applied at the 

 rate of 1 to 1] !>/.. toa gallon of water. 



Monograph, of Aphis ribis, J. H. L. Tlogel (Ally. Ztschr. Ent., 9 (1904), Nos. 

 17-18, pp. 321-834; 19-20, pp. 375-382, figs. .'>).— An elaborate discussion is presented 

 of the microscopic appearance <>f the egg, embryo, and various stages of growth of 

 this pest. The alternation of generations is discussed with especial mention of host 

 plants. 



The destruction of the eggs of phylloxera in winter by means of lysol, (i. 

 Cantin (Compt. Rend. Acad. Sci. [Paris], 139 (1904), No. 26, pp. 1232, 1283).— The 

 author lias tested the value of this method for 4 seasons and finds that lysol thus 

 applied is capable of keeping vineyards entirely free from phylloxera. The roots of 

 a number of vines were examined without finding a single tubercle on any of them. 



A life history of Cimbex fagi, A. J. Van Rossum ( Tvjdschr. Ent., 47(1904), Nos. 

 2-4, p}>- 69-98, pis. 3). — This insect is described in its various stages with especial 

 reference to the parasites which have been found to hold it in check. A brief account 

 is also given of breeding experiments with the insect and of parthenogenesis as 

 observed in the species. 



Monograph of the white ants of Africa, Y. Sjostedt (A". Svenska Vetensk. Akad. 

 Handl., 38 (1904), No. 4, > s '»/'-, pp- 128, pis. 4)- — Since the publication of the author's 

 monograph on this subject in 1900 much new material has been collected which 

 necessitated the publication of a supplement. Analytical tallies are given as aids in 

 the determination of species, and descriptive, economic, and biological notes are 

 presented on the various species described. 



Insects injurious to pecans, G. W. Herbick (Mississippi Sta. Bui. 86, pp. 42, 

 figs. 24). — The author has devoted considerable time to a study of the insect pests of 

 this nut and presents a preliminary report in the bulletin. The pecan pruner 

 (Oncideres texana) injures young pecans in nurseries by cutting into the twigs and 

 depositing eggs. The injury to the twigs is done before the eggs are laid. This 

 beetle is generally distributed throughout the southern States and feeds upon oak, 

 hickory, and persimmons in addition to the pecan. In controlling the pest it is 

 recommended that severed and infested branches be cut and burned in the autumn. 

 The pecan borer (Sesia scitula) is described in all its stages with notes on its life his- 

 tory. This insect confines its injuries to the trunk and branches above ground. It 

 causes great damage to young and old trees and frequently injures newly set buds. 

 In preventing the attacks of this pest it is recommended that care be exercised to 

 avoid injuring the bark of nursery trees, since the insect may enter into such wounds. 

 The borers may be dug out of infested branches in small nurseries. Various leaf- 

 eating caterpillars cause great injury to pecans and a number of them are discussed 

 in the bulletin. Among these mention may be made of Catocala viduata, Datana 

 angusii, and I), integerrima. These pests may be combated by spraying with arsen- 

 ical poisons, or the last two species may be readily destroyed in the caterpillar stage 

 on account of the habit of collecting in masses on the trunks of trees during the 

 molting periods. Descriptive, biological, and economic notes are also given on fall 

 webworm, Mallodon melanopus, white ants, oak pruner, pecan weevil, and pecan 

 budworm. The work of the white ants on pecans appears to be confined to the 

 seedling trees of the first year's growth, but these insects may also attack older trees. 

 In order to combat this pest it is necessary to destroy the whole nest either by hot 

 water or carbon bisulphid. The pecan weevil may be controlled by heating infested 

 nuts to a temperature of 125 to 150° F, or by fumigating such nuts with carbon 

 bisulphid, 



