TEOGOSITID.E— BYRRHID^E. 89 



TROGOSITID.^E. 



Thirteen species of this family have been found in the earher Tertiaries, 

 referred to three genera. Only a single one of these belongs to our conti- 

 nent. 



TROGOSITA Olivier. 



A widespread genus with a considerable number of species, of which 

 three occur in the United States. Ten fossil species have been found in 

 the older Tertiaries of Europe and Greenland. 



TrOGOSITA INSIGNIS. 



Trogosita insignis Heer, Flora foss. arct., 129, pi. 50, figs. 12, 12 be (1868); Flora 

 foss. Groenl., II, 144 (1883). 



Atanekerdluk, North Greenland. 



Sixteen species of this family have been found fossil, all but three in the 

 older Tertiaries. Two of these three are species of Byi-rhus, one each in 

 Europe and America, the same genus occurring also hi the older Tertiaries 

 of both countries; the third is an existing species of Cytilus reported from 

 the Bavarian Pleistocene. Of the thirteen species of six genera from the 

 older Tertiaries, five of two genera occur in the Old World, eight of five 

 genera in the New, the genus Byrrhus alone common to both. One American 

 genus is regarded as extinct. 



NOSODENDRON Latreille. 



Two species of this genus are found in North America, another in 

 Ceylon, while the fourth is cosmopolitan. A fossil species, the only one 

 known, occurs in Wyoming. 



NOSODENDEON TRITAVUM. 

 Nosodendron tritavum Scudd.. Tert. Ins. N. A., 499, pi. 7, fig. 36 (1890). 

 Green River, Wyoming. 



