TERTIARY ANIMALS. 



517 



Fig. 882.— Prodryas Persephone (after Scudder). 



and inclosed within may be seen perfectly preserved insects of many 

 kinds. Over 800 species of insects, and fragments of many species 

 of plants have been 

 found thus inclosed. 

 The degree of pre- 

 servation is marvel- 

 ous; even the most 

 delicate parts, the 

 slender legs, the 

 jointed antennae, and 

 the gauzy wings are 

 perfect. The manner 

 in which these insects 

 were entangled, in- 

 closed, and preserved, 

 may be easily observed 

 even at the present 

 day. The gum issu- 

 ing from Conifers is at first in the form of semi-liquid, transparent 

 tears. Flies, gnats, etc., alighting on these, stick fast, and by the run- 

 ning down of further exudations are enveloped and preserved forever. 

 The legs, both in the modern and the fossil resin, are often found 

 broken by the struggles of the insects to extricate themselves. The in- 

 sects of the Tertiary, like the plants, show a decided tropical character. 

 But probably the richest beds in insects yet found are at Florissant, 

 Colorado. Here fresh- water shales of Green River age are black with 



remains of insects of all orders now existing. 

 According to Scudder,* about 1,000 species 

 are recognizable, besides many plants, sev- 

 eral fishes, and a bird with feathers pre- 

 served. Of 30,000 specimens of insects in 

 all museums, about one half are from this 

 locality. Here, also, as in Europe, H} T men- 

 opters and Coleopters are most abundant, 

 and all the species indicate tropical climate. 

 Among the insects found here are seven 

 species of butterflies (only nine species are 

 known from all the rest of the world). A beautifully preserved speci- 

 men is shown in Fig. 882. At Florissant, in Eocene times, there was 

 a lake, and insects were cast ashore and accumulated in the manner 

 already described. Other Tertiary lake-deposits in the West are also 

 rich in insects (Fig. 883). 



Fig. 883.— Sackenia arcuata, from 

 Tertiary of Utah (after Scudder). 



* Bulletin of the United States Geological Survey, vol. vi, No. 2. 



