48 



TERTIARY INSECTS OF NORTH AMERICA. 



Order ^^.R^NEIDES Latreille. 



As stated above, by far the larger part of the fossil Arachiiides known 

 are true spiders, about one hundred and ninety species having been 

 described from the Tertiary deposits of Europe, and more than thirty being- 

 added to the total list in this volume. These last are distributed among; 

 the larger groups as follows: SaltigradjB (all Attides), three; Citigrada?, 

 none; Laterigrada?. (all true Thomisides), three; TerritelariiT?., none; Tubi- 

 telaria^ (Agalenides, one; Drassides, five; Dysderides, two) — eight; Retlte- 

 lariaj (all Theridides), four; Orbitelaria?. (all Epeirides), fourteen^ thirty- 

 two. By this it appears that nearly half are Epeirides, and that after these 

 the Drassides are best represented. A comparison of this result with the 

 fossil spiders of Europe is shown by the following table, in which the per- 

 centages of the groups represented are compared in each country with the 

 total representation in each : 



Pirveiitaijes of ijronps of Tertiarij spiders in, Europe and in .-imerica. 



Suborders. 



SaltigradiB . 

 Laterigradie 

 TubitelariiB- 

 Retitelaria) . 

 Orbitelaria'.. 



98 



This shows that America is far the richer in Orbitelaria", and Europe 

 much better represented in Retitelarije, less but still considerably better in 

 Laterigradpe and Tubitelarise, while the Saltigradse have an almost equiv- 

 alent re))resentation in the two countries. 



If, however, we eliminate from the inquiry the species entombed in 

 amber, and compare only those recovered from the rocks in which they 

 have been preserved, we shall reach perhaps a more just comparison, 

 although the data will be far more meager, America with its thirty-two 

 species being actually better represented than Europe with its twenty-two 

 species, all belonging to the same five larger groups which are represented 

 in America. 



