158 EXPERIMENT STATION RECORD. [Vol.38 



Studies in greenhouse fumig-ation with hydrocyanic acid. — Temperature 

 and moisture as factors influencing the injury of plants during fumiga- 

 tion, W. MoonK {Rpt. State Ent. ^finn., 16 {1915-16), pp. 93-108, figs. 6).— The 

 studies here reported are summarized as follows: 



"Hydrocyanic acid may enter a plant either through the stomata or directly 

 through the cuticle. The amount of hydrocyanic acid which will enter the 

 cuticle of the plant depends upon the thickness and the degree to which it has 

 been cutinized. 



" Moisture on the leaves aids the gas to penetrate, but is not so important a 

 factor where the house contains only plants with thick, heavy cuticles. Mois- 

 ture may be present on the leaves from sprinkling the plants or from exudation 

 of water from the water pores. High relative humidity at the time of fumiga- 

 tion aids the penetration of the gas through the cuticle, thus favoring injury. 

 High relative humidity after fumigation tending to prevent evaporation of 

 hydrocyanic acid in the cuticle of the plant tends to increase injury to the 

 plants. Low temperatures at the time of fumigation and after act in a similar 

 manner to a high relative humidity. High temperature by increasing evapora- 

 tion produces results similar to a low relative humidity. Both high relative 

 humidity and low temperature have less influence on plants with thick, waxy 

 leaves." 



Notes on American Tingidse with descriptions of new species, H. Osborn 

 and C. J. Drake (Ohio Jour. Set., 17 {1911), No. 8, pp. 295-307, figs. 2).— This 

 paper presents notes on 33 species, of which 10 species and 1 variety are de- 

 scribed as new. Information on the food plants of many of the species is 

 included. 



The sugar cane froghopper in Grenada, J. C. Hutson {Agr. Xews [Bar- 

 bados], 16 {1917), No. 389, p. 90).— Investigations made by C. B. Williams in 

 December, 1916, show that Tomaspis saccharina has been established in Grenada 

 for many years. Actual damage to canes was reported from two estates, on 

 one of which the injury was fairly severe. 



The common mealy bug and its control in California, R. S. Woglum and 

 J. D. Neuls {U. 8. Dept. Agr., Farmers' Bui. 862 {1917), pp. 16, figs. //).— Con- 

 trol measures for the citrus mealy bug, which continues to spread in California, 

 are discussed under the headings of fumigation, spraying, and control by natural 

 enemies. The sphere of usefulness of each and the way in which they may be 

 combined to secure complete control are pointed out. 



The banding of trees with a mixture consisting of sulphur and a sticky 

 material to keep the Argentine and other ants off the trees forms an important 

 part in its control. Where insect enemies are few or absent, or where the 

 mealy bugs are themselves heavily parasitized, the trees should be sprayed or 

 fumigated and colonies of effective enemies introduced. 



The black fly and methods of controlling it {Agriculture [Cuba], 1 {1917), 

 No. 5, pp. 43-49, figs. 3). — This is an account of Aleurocanthus ivoglumi, dis- 

 covered in Cuba in August, 1915, as previously noted (E. S. R., 35, p. 552), and 

 measures of suppression now under way. The pest has been recently found in 

 various gardens at Vedado, Havana. 



Chermes attacking fir trees, N. A. KHOLODKOvsKii {Khermesy Vred{ashchie 

 Khvoinym Depev'iam. Petrograd: Glav. Uprav. Zemleustr. i Zemlcd., 1915, pp. 

 91, pis. 7, figs. 6). — The author deals at length with the chermes occurring on 

 fir trees, 11 species being considered. 



Some notes on the mealy plum aphid, Hyalopterus pruni, F. C. Willcocks 

 (Btil. Sac. Ent. Egypte, 9 {1916), No. 2, pp. 33-37; aJ)s. in Rev. Appl. Ent., Ser. 

 A, 5 {1917), No. 5, p. 188). — This aphid, which is said to be prevalent in Egypt 



