26 HeiT N. Damin on Parthenogenesis in Spiders. 



VII. — On Parthenogenesis in Spiders. 

 By N. Damin *. 



For the preservation of the species the union of two separate 

 sexes of the species is necessary. At the same time, how- 

 ever, multiplication without a union of the sexes, that is to 

 say, an asexual reproduction, has been proved to take place 

 in the vegetable and animal kingdoms. 



To the latter class of phenomena belongs the virgin repro- 

 duction, or iiarthenogenesis^ which occurs also among higher 

 animals. In such cases the egg-cells are capable of devel- 

 oping into embryos without previous impregnation. 



Parthenogenesis is met with especially in the great phylum 

 Arthropoda. It has been observed in the case of bees, wasps, 

 and gall-flies (Cynipida?), in the silkworm-moth and in 

 Psychidse, in Tineida, midges, Aphida3, and Coccidai, as well 

 as in the Phyllopoda and Ostracoda among the Crustacea. 

 Considering the frequency of parthenogenesis among Arthro- 

 pods, the question arises whether the phenomenon does not 

 also occur among spiders, which belong to the same division 

 of the animal kingdom. Hitherto, however, no case of 

 parthenogenesis in these animals has become known f. 



After having observed living spiders for many years, I am 

 now in the happy position of being able to establish an 

 instance of parthenogenesis among the Araneina also. 



In the spring of 1891 I placed two living specimens of 

 Filistata testacea, Latr.J, in separate glass tubes, in order to 

 observe them from day to day. One of these spiders, of which 

 1 siiall speak, twice underwent ecdysis in the course of the 

 summer of 1891, and in the spring of 1892 once again — a 

 ]jroof that when I shut it up it was still immature, i. e., 

 according to the previous state of our knowledge, incapable of 

 reproduction. On the 8th of July, 1892, this female spun on 

 the side of the tube an egg-sac shaped like a tobacco-pouch, 

 similar to that of Microimnata. I was not surprised at this, 

 since I had frequently noticed that spiders spin a cocoon and 

 lay eggs without ever having had intercourse with a male. 

 After a few days, however, the eggs in such envelopes were 



* Translated from the ' Yerliaudlurigen der k.-k. zoologiscb-'botanischen 

 Gesellscliaft in Wien,' Jalirg. 1893, xliii. Bd., II. Quaital (Wien, 1893), 

 pp. 204-2U6. 



t [An in-^tance of provable partlienogenetic reproduction in the case of 

 Tetjenaria Guyonii, Guer., -was recorded by Mr. F, M. Campbell (Jom'n. 

 Linn. Soc. x\i. pp. 536— J38) in 1882. — Tkansl.] 



\ Filistata hicolor, Luc. (' Exploration de I'Algerie '), and Teratodes 

 attalicus, C. Koch (' Die Arachuiden,' v.-), are synonyms of this species. 



