INTRODUCTION. 3 
possible reference elsewhere has been suggested, this suggestion will hardly 
stand the test of investigation, and the matter remains where I left it; and 
in the present work attention is directed to another group—the Coleopterous 
family Rhynchitidee—in which it has been found necessary to establish a 
new subfamily group for an abundant and varied series of insects from our 
Tertiaries. 
In studying the Rhynchophorous Coleoptera, I have, for the first time, 
made use of all the material which has been collected in the most recent 
as well as in former years; and have been able, therefore, to do justice to 
the other localities of fossil insects, as well as the now famous locality of 
Florissant, Colorado, and I find that there is no family of American Rhyn- 
chophora paleontologically more interesting than the Rhynchitide. In point 
of numbers alone the species of this group form more than 10 per cent of 
‘the fossil Rhynchophora of North America, while in the existing fauna the 
Rhynchitidze comprise less than 24 per cent of all the Rhynchophora. Our 
recent Rhynchitide are separated by Le Conte and Horninto two subfamilies, 
~one of which comprises the bulk of the family, while a single species is sepa- 
rated to form the other, the Pterocolinze. This differs from the Rhynchitine, 
among other things, by the antennz being inserted much nearer the eyes, 
by the wide separation of the fore and middle cox, and by the broad side 
pieces of the metasternum. The Pterocolinz are not represented among 
the fossils, but all the genera of Rhynchitinze now existing in our fauna are 
recognized, as well as a new generic type. These, however, are but a 
mere fraction of the fossil Rhynchitide, the bulk of them being separated 
as a new subfamily—the Isotheinz, a subfamily characterized by the mod- 
erate separation of the fore and middle coxe, and by the insertion of the 
antenne, which is before the middle of the basal half of the straight and 
porrect beak. These characters show an approach to the Pterocolinze rather 
than to the Rhynchitinee, but they have narrow metasternal side pieces. This 
subfamily, thus clearly distinguished, is, for Rhynchitidee, exceptionally rich 
in forms, since it contains no less than seven genera and thirteen species, 
about equally divided between two distinct tribes, all extinct. This brings 
the total number of fossil American Rhynchitidee up to four-fifths that of 
