94 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



Mr. Sanderson differed from this view, expressing the belief that 

 there were important i^hysiological differences due to climate. This 

 had been forcibly illustrated by the differences in effectiveness of 

 various insecticides on the San Jose scale in the Southern and North- 

 ern States in the percentage of oils required to kill the scales. 



Mr. Newell, referring to previous remarks on the factors influen- 

 cing the abundance of aphides, said that he had noticed that the 

 application of Paris green to the cotton ]:)lants caused an enormous 

 increase in their numbers. 



Mr. Summers said that he believed that the number of aphides 

 was related more closely to the number of their predaceous enemies 

 than to any other factor. When these were absent from any cause, 

 either by chance or because of unfavorable climatic conditions, the 

 aphides had such enormous powers of reproduction that they would 

 soon become abundant. 



Mr. Hinds said that in using Paris green for the boll weevil the 

 Coccinellidae were killed and the aphides multiplied in consequence. 



Mr. Schwarz said that he was very much surprised that among all 

 the insects mentioned in the preceding papers there was not a single 

 new importation from a foreign country ; neither were there any new 

 American species. He could not regard Cicada tiigriventris "' as new. 

 It has been received by the Department at Washington from southern 

 Louisiana. He belieA^ed that when fuller collections were made it 

 would probably be found that a com})lete series could be obtained, 

 extending from the present noted locality in Louisiana westward 

 through Texas into Mexico, where the species is common. 



Mr. Osborn thought that while Cicada nigrirentris might possibly 

 have been incidentally noticed heretofore, Mr. Newell's paper had 

 brought out in great detail some entirely new habits of the family. 

 So far as is known, no other Cicada has a similar method of oviposi- 

 tion. It is true there is one prairie species that is known to live miles 

 from timber, and which therefore presumably must oviposit in her- 

 baceous plants. While there is some doubt about the determination 

 of Mr. Newell's species, it certainly belongs to the mgriventris group, 

 and may be merely a variety of it. 



Mr. Newell said that it seemed very improbable that Cicada nigri- 

 ventris should be found to extend continuously through Texas and 

 into Mexico. A strip of territory about 50 miles wide along the 

 western side of Louisiana and extending from Arkansas to the Gulf 

 had been watched very carefully during the past year, and large 

 general collections of insectjs made in different localities, and if the 

 species had occurred anywhere in it in abundance it would certainly 

 have been found. 



o See footnote, page 52. 



