1240 The Zoologist — June, 1868. 



Numerical Proportion of Sexes among Spiders. 

 By the Rev. Octavius Pickard-Cambridge, M.A. 



The following facts relating to the numerical proportion of the 

 sexes among spiders may be of interest to Mr. Darwin, who will no 

 doubt see them if inserted in the ' Zoologist.' 



In an extensive group of the family Epeiridae, comprising several 

 genera (Gasteracantha, Acrosoma, Pycuacantha, Plectana), I have 

 never yet seen an example of the male sex. During a continental 

 tour in 1864-5, 1 inspected collections of Arachnida in the Natural 

 History Museums of Vienna, Milan, Berlin, Frankfort and Ley den : 

 in all of these, if I remember rightly, there were females of this group, 

 but certainly no males. The British Museum, as well as the Oxford 

 University Museum, contain large collections of this group, but 

 I could not detect in either an example of the male sex ; nor do 

 I believe that any one of this sex has ever yet been described by 

 arachnologists ; Walckenacr alone describes seventy-nine species, but 

 all are evidently females. Koch (die Arachniden) describes many 

 more, but no males. Morell indeed, in a paper entitled " Ureja 

 exotiska Epeirider" (Ofversigt. af Kongl. Vetenscaps-Akademicus 

 Forhandlungen, 1859, p. 299), describes two males, which he includes 

 in this group : 1 have not this work by me, but on a hasty perusal of 

 the paper, last October, there seemed to me reason to doubt whether 

 the two spiders described really belonged to the group in question : 

 supposing, however, that they do, it is still a remarkable fact that out 

 of a group numbering upwards of one hundred described species, 

 males of two only should have been observed; and this singularity is 

 increased when we consider that the group comprises some of the 

 most curious of spider-forms — forms which invariably attract the 

 attention of even the most unscientific collector. I have seldom seen 

 a collection of tropical insects, whether sent home dry or in spirits of 

 wine, that did not contain specimens of these anomalous-looking 

 spiders.' 



In all probability the males of this group are exceedingly small 

 compared to the females, and for this reason perhaps they have been 

 overlooked by collectors : if I were to hazard a conjecture as to their 

 probable appearance I should say they would look like little horny 

 and more or less spiny ticks. The idea that their minuteness has 

 caused them hitherto to escape notice is borne out by the known 



