26 ENTOMOLOGICAL SOCIETY 



shorter apical portion of the same, the greater or smaller extent 

 of the thickened rim, etc. 



3? Type. Ventral plate without such tooth ; apical portion not 

 triangularly produced but broadly rounded ; edge coarsely ser 

 rate ; terminal point represented by a broad tooth. 



Here belongs a single species which is possibly undescribed. 



Mr. Schwarz exhibited samples of white and black insect 

 pins made by Schliiter of Baden, Germany, and now offered for 

 sale by Queen & Co. He said that from a short experience 

 these pins appeared to him to be superior in many respects to 

 the Klager pins as now obtained in the market. 



APRIL 6, 1893. 



In the absence of the President, Vice- President Ashmead pre 

 sided. Ten members and one visitor were present. 

 Dr. Marx presented the following paper : 



DEGENERATION BY DISUSE OF CERTAIN ORGANS IN 



SPIDERS. 



By GEO. MARX. 



A strange example of retrogradation in organs by disuse I have 

 noticed among some spiders of the Fam. DrassidaB collected in 

 the subarctic region of our continent: The genus Gnaphosa is 

 known to make no web, their faculty of spinning being con 

 fined to making loose threads in crevices under bark and stones, 

 to cocoon covering, and occasionally they issue a drag-line while 

 running. 



In the northern region their active life is so short that they 

 seem to have no need to use their spinning organs at all, and these 

 organs the external spinnerets as well as the internal spinning 

 glands are apt to retrograde gradually and become rudimentary 

 or they are lost altogether. This is the case in our' Gnaphosa 

 conspersa Thorell, of which I possess specimens in my 

 collection from Alaska, Lake Superior, and Lake Klammath, 

 Oregon. Here the two superior and the two median spinnerets 

 are entirely wanting, while the two inferior spinnerets are fully 

 developed. The anatomical change is confined to the absence of 

 eleven large glands (either tubuliform or ampulaceas and nine 

 median glands) , while in the inferior spinnerets there are retained 

 three large and about twenty smaller pyriform glands. The 

 product of the pyriform glands is the guy-rope or drag-line, while 



