Deoeniber, "08] .ToURXAL of economic entomology 413 



data condensed in a series of tables afCords an excellent basis for estimating 

 the dosage. The work of the past two years has demonstrated the practica- 

 bility of solving this big insect problem of Florida and other citrus districts 

 on the Gulf coast. The practical value of the bulletin is greatly increased by 

 the excellent series of original illustrations. It can not but prove of great 

 service to citrus growers. The author is to be congratulated upon having 

 covered the subject in such a comprehensive manner. 



A Few Orchard Plant Lice, by C. P. Gillette and E. P. Taylor, 

 Colorado Agrieultiiral Experiment Station. Bulletin 103, 1908, p. 1-48. 



This bulletin gives in concise form the results of extended observations and 

 experimentation upon a number of the more injurious plant lice occurring in 

 orchards. Two well executed colored plates constitute an extremely valuable 

 addition to this publication. The life history notes and the results secured 

 with various insecticides will be especially valuable to the entomologist. An 

 abbreviated edition of this publication without the colored plates has been 

 Issued by the station as Bulletin 134. 



The European Elm Scale, by Samuel B. Doten, Nevada Agricul- 

 tural Experiment Station, Bulletin 65, 1908. p. 1-34. 



This bulletin gives a detailed biological account of Gossyparia spuria Mod. 

 based on original observations. Its value is greatly enhanced by excellent 

 reproductions from an extensive series of enlarged photographs and numerous 

 drawings showing structural details. Experiments with lime-sulphur wash, 

 kerosene emulsion and scalecide are discussed, the last named apparently 

 giving the best results, though the author inclines strongly to recommend 

 thorough spraying with a forcible jet of water just before the leaves begin to 

 show and again in June before the young scale insects appear. This bulletin 

 is an important contribution to our knowledge of this pest. 



A Contribution to Our Knowledge of Insecticides, by C. T. ]\Ic- 

 Clintock, E. M. Houghton and H. C. Hamilton. A Reprint from 

 the Michigan Academy Sci. 10th Eeport, 1908, p. 197-208. 



This paper records the results obtained in a very suggestive attempt to stan- 

 dardize the insecticidal properties of a number of contact insecticides and to 

 show the relationship existing between insecticidal, germicidal and toxical 

 values. The authors conclude that there is not any close connection between 

 the three and urge the importance of establishing standard tests for the accu- 

 rate comparison of insecticides. They found in their work that the common 

 bedbug was a most satisfactory insect for making comparative tests. They 

 state that chemical standardization of contact insecticides is at present im- 

 possible, since two substances having essentially the same chemical composi- 

 tion may vary enormously in their insecticidal values. It is to be hoped that 

 this paper will stimulate other investigations along similar lines. 



Fungous Diseases of Scale Insects and White Fly, by P. H. Rolfs 

 and H. S. Fawcett, Florida Agricultural Experiment Station, Bulle- 

 tin 94, 1908, p. 1-17. 



Climatic conditions in Florida are unusually favorable for the development 

 of fungous diseases. The authors have in this bulletin given brief popular 



