OF WASHINGTON. 219 



to the prejudice against the use of the arsenicals, which has 

 interfered somewhat with the work of the Commission, and 

 which, at the request of Mr. Sessions, he had done his best to 

 remove by a statement of the facts regarding these insecticides, 

 -showing that their use, with ordinary care, is free from dan 

 gerous consequences to live stock or man. He stated that he 

 believed that most of the cases reported of animals being poi 

 soned by these arsenicals are hardly to be relied upon, and that 

 in most instances he believed the death had resulted from some 

 other cause. He said, in reference to the work of the Commis 

 sion, that however carefully it might be done, the extent of 

 the territory covered by the insect and the inherent difficulties 

 of the task, made him very doubtful of ultimate success in 

 eradicating the pest. He gave some facts which he had gath 

 ered from conversation with Prof. Shaler during his recent trip 

 to Boston, regarding the manner in which this insect had been 

 allowed to escape by Trouvelot. Prof. Shaler had known 

 Trouvelot very well, and said that Trouvelot had left a batch 

 of eggs on a window-sill and allowed them to be blown away. 



He also referred to a spider, determined by Mr. Banks as 

 probably Pardosa albomaculata Em. , which had been found by 

 Mr. Wm. H. Edwards to seize butterflies on the wing. He 

 referred again to the parasite obtained from Eleodes suturalis, 

 the cocoons of which parasite he had exhibited and described 

 at .the previous meeting of the Society. He mentioned that the 

 imago had since been obtained and turned out to be a species 

 of Perilitus, a fact of considerable interest because of the close 

 relationship of this parasite with the one bred from Megilla 

 maculata, and described and figured in Insect Life, Vol. I, as 

 Perilitus americanus. This parasitism of Eleodes was not so 

 exceptional, therefore, as Perilitus affected a number of Cole- 

 optera in the imago state. 



Mr. Howard referred to the Rose insect mentioned by Prof. 

 Riley, and said that the common Rose Chafer had never been 

 brought into the Department from the District, and that 

 although it had occurred abundantly in neighboring localities 

 it seemed rarely to do much damage in the immediate vicinity 

 of Washington. He accounted for this partly by the nature 

 of the soil of the District. 



