OF WASHINGTON. 87 



Mr. Schwarz said that Mr. H. Lucas had already performed 

 this experiment on himself repeatedly without experiencing 

 any effect. 



Dr. Marx called attention to the fact that the opening lead 

 ing from the chelicera to the poison sac is extremely minute, 

 which, in connection with the small size of the latter, would 

 indicate that a very small quantity of poison only could be in 

 jected into the wound made by the spider. 



Dr. Fox inquired how long the spiders experimented with 

 had been kept in confinement. 



Dr. Marx replied three to four weeks, during which time 

 they had been fed on flies. 



Mr. Howard said that the first experiment was unsatis 

 factory and inconclusive. In the introduction of the poison 

 sacs entire, it was very uncertain whether the poison was 

 liberated before it had itself lost its toxic quality, if in fact, 

 as Dr. Marx himself stated, it was not thrown out with the 

 pus arising from the wound. 



Dr. Marx promised to continue his experiments. 



Discussion followed on the possibility of this spider, with 

 its comparatively small jaws, piercing the skin of man, the 

 conclusion arrived at being that in the usually exposed 

 parts of the body this would be well nigh out of the 

 question. 



Mr. Ulke gave an interesting account of the habits of 

 Tachys incurvus Say, which he had found in large numbers at 

 Pen-Mar, Pa. , in the nests of Formica exsectoides^ and which is 

 the first North American Carabid known as truly myrmecoph- 

 ilous. He also spoke of the habits of a myrmecophilous 

 Staphylinid observed at the same locality. A large under 

 ground colony of an undetermined species of Formica was 

 accidentally disturbed, and among the multitude of ants rush 

 ing forth from the entrance hole there were numerous speci 

 mens of this Staphylinid, which rapidly took wing and 

 escaped. Only two specimens could be secured, which proved 

 to be an undescribed species allied to Myrmedonia, and not 

 mentioned by Schwarz in his list of myrmecophilous Coleo- 

 ptera. 



