IQOl] ENTOMOLOGICAL NEWS. 253 



Another interesting paper by Dr. Reh is on the resistence of certain 

 species of Diaspince to external influences, from the " Biologischen 

 Central Blatt," December, 1900. In this he gives the results of a long 

 series of experiments made with all sorts of liquids and gases, mainly on 

 certain species of Diasfns and Aspidiotus including A. pemiciosus. The 

 results are sometimes a little unexpected and not easily explained, as 

 when complete submergence in 90 per cent alcohol for several hours 

 failed to kill, and when hydrocyanic acid gas left living examples after 

 a twenty four hours' exposure. But even painting over with chloro- 

 form and kerosene proved more or less ineffective and it would seem, 

 theoretically, that such substances and such processes would not be of 

 much practical use. Nevertheless we know that the gas and the kero- 

 sene really are very effective in the nursery and orchard. 



The only positively fatal applications were coverings with rape oil and 

 vaseline. These, though rather slow, were absolutely certain and are 

 classed as methods of excluding air. The paper concludes, freely trans- 

 lated, as follows : 



"As the most effective method, aside from the mechanical destruction 

 of the insects, my results indicate the exclusion of air, which is most 

 easily obtained by covering with oil or fat, and surely kills all the Hce." 



This is important, because it confirms experimentally what I have ad- 

 vised practically in the orchard. Crude petroleum leaves a thin vaseline 

 coating which, eventually, kills everything in its way, even the tree, if it 

 is present in excessive amount. It kills by excluding air, of course, but 

 perhaps not quite in the way indicated by Dr. Reh. The material forms 

 no coating over the scale — it penetrates through it and, sooner or later, 

 comes into contact with the insect itself, closing its breathing operations 

 in the most effective manner. But this is different from the mere exclu- 

 sion of air, as where, for instance, by a resin mixture applied to the outer 

 surface, the scale is practally sealed to the tree, none of the substance 

 coming into contact with the insect itself. I would quite expect a long 

 life for an insect so covered, and would not be surprised if, in the mere 

 process of growth, the seal would not be in time broken. — ^John B. 

 Smith. 



Doings of Societies. 



A regular stated meeting of the Feldman Collecting Social 

 was held this evening, September i8th, at the residence of Mr. 

 H. \V. Wenzel, 1523 S. 13th Street, 11 members present. The 

 President, Mr. Charles W. Johnson, in the chair. The Minutes 

 of the last meeting were read and approved. 



Mr. H. Wenzel exhibited a series of seven boxes containing 

 his collection of Lac/mosterna which he had worked up during 



