SCUDDER. ] TERTIARY LAKE BASIN OF FLORISSANT. 285 
Libellulina come next with sixteen species (only indicated in America), 
- of which no less than ten are larvae or nymphs; then Gomphina with 
seven species (not yet detected here); and Aeschnina with six species 
(against three in America). 
Twenty-six specimens of Termitina have been found, belonging to six 
species and three genera; among the specimens is a single worker, with 
one exception the only one that has ever been found fossil; four of the 
species and two genera belong to the section with branched, the others 
to that with unbranched, scapular vein. This is the same proportion as 
holds with the sixteen species of the European teritaries, where eleven 
belong to the first, five to the second section; of living types, on the 
contrary, only 35 per cent. belong to the first, 65 per cent. to the second 
section. Three of the species belong to a distinct genus which I call 
Parotermes, apparently peculiar to America, but possibly including some 
from the European tertiaries; another is doubtfully referred to Hodo- 
termes, which has furnished fossil species from several localities in 
Europe, as well as among living forms; while the other two probably 
belong to Eutermes and are allied to species from Radoboj, placed with 
many modern types in this group. Calotermes, which has furnished 
species from amber and the Rhenish basin; Termopsis, which has more 
fossil (amber) species than recent; and Termes proper, which is repre- 
sented at Oeningen and Radoboj, as well as in amber and on the Rhine— 
all seem to be wanting at Florissant; the composition of the tertiary 
white-ant fauna of Florissant, therefore, differs considerably from that 
of any locality in Europe; but it most nearly resembles that of Radoboj 
in Croatia, where a like number of species has been found. 
A single plate with thirty-two figures is devoted to the Arachnida, of 
which there are 32 species and 78 specimens; allof them are Araneides 
or true spiders. To show the bearing these have upon our knowledge of 
fossil Arachnids, it may be well to enter in this single instance into a 
few details. 
Up to the present time a little more than 250 species of tertiary Ar- 
achnides have been described. Of these about 190 are true spiders, 
while the remainder are mostly Acarina, Opiliones, or Chernetidae; all 
but a single species are from European beds, and nine-tenths of them 
are preserved to us in the eocene amber. Were this means of restoring 
the ancient tertiary fauna unknown to us, our information at the present 
day would be based upon 24 species, although in addition to these half 
a dozen more are indicated by simple reference to genera or families. 
This number is exceeded by those already found at Florissant. 
Whether we examine the American or European species preserved in 
stratified deposits (i. e., excluding amber), we find an almost total ab- 
sence of any but true spiders or Araneides; in each (including a tick 
from the beds at Green River, Wyoming), a single species of Acarina 
is known, though a number of others undescribed are credited to Kuro- 
pean strata. In Prussian amber, on the other hand, though Araneides 
are vastly in the majority, the other groups of Arachnida form twenty- 
seven per cent. of the entire number of species. 
This greater proportion of true Araneides in tertiary deposits, a pro- 
portion intensified at the present day, can scarcely be well compared to 
what we find in the older deposits, from the extreme paucity of their 
remains in the latter. Brodié has found a single species (which he con- 
siders a true Araneid) in the secondary rocks of England; and the Kuro- 
pean Jura has furnished merely half adozen Arachnids (nominal species, 
perhaps reducible to four), of which only a single one is referable to the 
Araneida,—Hasseltides, considered by Weyenbergh one of the Agal- 
