186 



-9. H. Scudder — Hffict of Glaciation, etc. 



Here it will be seen that in the northern percentage of both 

 genera and species, the East lags a little behind the West, but 

 it is only a very little, and it is much more than made up by 

 the considerably larger percentage in the East of the genera 

 common to North and South. 



I have also tabulated the species reported as found common 

 to the northern and southern districts on each side of the con- 

 tinent and find that about 16 per cent of all the western 

 species are common to the two districts, while about 35 per 

 cent of all the eastern are common to the drift- covered and 

 driftless areas. 1 append a table of these numbers. One 

 difference between this table and the previous one is that here 

 the common species form the base, while in the previous one 

 the common genera form the base ; hence a genus represented 

 in the two districts, but only by distinct species, does not 

 appear in this table, but only in the previous one. Seven 

 families in which there are no species recorded as found in 

 two regions are omitted from the list. 



Table of 



the species common to pairs q 



f regions. 





Families. 



S + N 



N+D 



D + E 



Families. 



S + N 



N + D 



D + E 



Cicindeliche 



2:5 



2:22 



Throscidae 







2:5 



Carabicte 



20:46 



14:25 



62:245 



Buprestidfe 



5:10 



4:6 



16:62 



Amphizoidse 



1:1 







Lampyridas 



5:6 



3:3 



22:65 



Haliplidae 







2:6 



MalachidtB 



3:3 





5:12 



Dytiscidae 



8:12 



4:7 



22:67 



Clendae 



2:3 



2:2 



12:18 



Gyrinidae ■ 





1:2 



2:10 



Ptinidas 



3:3 





23:28 



Hydrophilidae 



4:6 



2:2 



11:37 



Cupesidse 







1:2 



Silplridae 



13:17 



7:12 



15:43 



Cioidte 







3:3 



Scydmasnidas 



1:1 





2:7 



Lucanidas 



3:3 





5:8 



Pselaphidas 



1:1 





14:36 



Scarabaeidse 



6:9 



2:3 



36:106 



Staphylinidae 



15:29 



13:27 



57:189' 



Spondylidas 



1:1 



1:1 



1:1 



Trichopterygidae 



1:1 





3:5 



Ceranibycidae 



17:20 



12:13 



66:155 



Scaphidiidas 







3:7 



Chrysomelidas 



15:19 



12:14 



59:164 



Phalacridaa 



1:1 





2:5 



Bruchidae 







1:7 



Corylophidse 





1:1 



3:5 



Tenebrionidae 



10:14 



1:1 



.28:45 



Coccinellidas 



8:10 



6:7 



17:45 



Cistelidas 







7:11 



Endomychidse 



1:1 





7:8 



Lagriidae 







1:1 



Erotylidse 







7:20 



Melandryidas 



1:1 



2:2 



19:26 



Colydiidas 



3:3 



1:1 



10:11 



Pythidae 





1:1 



1:1 



Rhyssodidas 







2:2 



Oedemeridas 







4:5 



Cucujidag 



3:3 





8:19 



Mordellidag 



1:1 





4:31 



Cryptopliagidae 







6:6 



Anthicidae 







5:24 



Mycetophagidas 



1:1 



1:1 



6:12 



Pyrochroidre 





1:1 



2:2 



Dermestidas 



3:5 



3:3 



8:16 



Meloidse 



3:4 





7:15 



Histeridae 



2:5 



1:1 



11:51 



Ehipiphoridae 







1:5 



Nitidulidse 



4:4 



4:4 



18:33 



Stylopidas 







1:1 



Latridiidaj 







3:6 



Rhiuomaceridae 







1:1 



Trogositidas 



3:3 



1:1 



6:16 



Rhynchitidse 



1:1 



1:1 



4:8 



Derodontinte 







1:1 



Attelabidas 







1:5 



Byrrhidae 



1:2 





1:1 



Byrsopidas 







1:1 



Georyssidas 







1:1 



Otiorhynchidse 



5:5 





6:6 



Parnidas 







6:13 



Curculionidae 



10:16 



7:7 



47:117 



Heterocerida? 



1:1 



1:1 





Brenthidfe 







1:1 



DascylHdae 





1:1 



7:12 



Calandridas 



1:1 



1:1 



6:16 



Rhipiceridag 







3:5 



Scolytidae 



7:10 



6:6 



21:39 



Elateridas 



9:14 



10:15 



41:119 



Anthribidae 

 Totals 





1:1 



128:174 



6:7 





205: -502 



794:2083 



