6 TERTIARY RHYNCHOPHOROUS COLEOPTERA. 
divided between those which are predominantly North American and those 
which are tropical American, but often extend to our southern borders. Of 
the 31 new genera (with 57 species) little can be said in this particular, but 
nearly half of them may be regarded as most closely allied to American and 
especially tropical American types; so that on the whole the American, and 
especially the tropical American, type predominates. It should be remarked, 
however, that the resemblance of the fauna to that of temperate North 
America is undoubtedly greater in appearance than in reality and will very 
probably be changed to some extent when the various species here recorded 
are better known; for, in default of characters which if preserved might 
materially change the alleged affinities of the various forms, it has seemed 
advisable to refer most of them to existing genera, and my opportunities for 
examining tropical and subtropical types have been very limited. Where 
characters of real importance exist, the insects generally show the preva- 
lenee of structural differences, often considerable, from modern forms. 
The number of new genera here proposed is certainly greater than has 
been usual in the study of Tertiary insects, but this I believe to be a neces- 
sity if we are to apply the same methods to their study that we do to the 
study of modern insects; nor is the number surprising, since not a single 
species is found in our Tertiary deposits which can possibly be referred to 
an existing form or even to any of those which have been described from 
the European Tertiary rocks; and I am convinced that the actual difference 
between the older Tertiary ‘and existing types is far better expressed by the 
separation of the former from the latter in generic nomenclature whenever, 
the characteristics being sufticiently preserved, they show any such differ- 
ences as among modern types are regarded as warranting generic separation. 
It must be confessed, however, that among the fossils the Coleoptera are 
far less apt to have those characteristics of their structure which are seized 
upon for generic disassociation sufficiently preserved to warrant great cer- 
tainty or insure exactitude and that those orders which display wing neu- 
ration afford far better means of judgment, on account of the commonly 
better preserved remains of just those parts which are largely relied upon 
for generic discrimination. 
The localities at which the species described below have been ob- 
