44 
rOHJLAR SCIENCE REVIEW. 
lake, and under conditions such as are favourable to tne 
preservation of insects ; and accordingly large numbers 
have been obtained from this interesting formation. The 
orders Diptera , Orthoptera , Neuroptera , and Hymenoptera are 
abundantly represented by fossil gnats, cockroaches, dragon- 
flies, and huge ants allied to exotic genera. Out of sixty-four 
species described, the beetles number eighteen. The hemi- 
pterous insects follow next, with fourteen species ; the Diptera 
with thirteen, and the Orthoptera with ten. The beetles are 
chiefly herbivorous kinds. 
When we come to the Tertiary strata undoubted Lepidoptera 
make their appearance. There is no longer any zoological 
doubt as to what they are. But this is the period when true 
flowers began to be abundant, and therefore it is significant 
we should find specialized flower-loving insects appearing 
at the same time. As a rich fossil flora, containing true 
flowers, has been found in formations as old as the Lower 
Cretaceous in Greenland, it is possible that Lepidoptera appeared 
before the Eocene period. Nine species of fossil butterflies 
are found in strata of the latter age at Aix in Provence. 
The Miocene strata of Switzerland have yielded an immense 
number of species of fossil insects, which have been described 
by Professor Heer. In beds of this age at Radoboj in 
Croatia, three species of butterflies have been found; one of 
them singularly allied to an Indian species. In this formation 
the Hymenoptera are very abundant. From the Swiss Miocene 
at CEningen Professor Heer has obtained nearly nine hundred 
species of fossil insects, of which the Coleoptera number no 
less than five hundred and eighteen. Not only do we find 
these Miocene beetles differentiated and adapted to all the 
habits of life which their Oolitic predecessors had already 
possessed, but for the first time we come across true flower- 
haunting beetles, belonging to groups actually specialized in 
our own day to particular genera of flowers. So striking is 
this that Professor Heer infers the existence of such flowers 
(although they have not as yet been found) during the Miocene 
epoch. The fossil Hymenoptera of CEningen number eighty 
species, and among these are those highly specialized forms, 
such as bees, which are always associated with flowers. Three 
species of butterflies are all which have as yet been recognized. 
It would seem probable, therefore, that bees appeared before 
butterflies, and obtained their remarkable specialization by 
being adapted to the earliest of the flowering plants. 
Near the White and Glreen Rivers, bordering on the territories 
of Utah and Colorado, an immense tertiary deposit has been 
explored by the United States surveyors. Its shales have been 
found crowded in places with insect remains, including even the 
