80 THE CLASS OF INSECTS. 



158 ; those that are common to l)otli hemispheres forming then 

 more than two-thirds of the whole number, while of the actual 

 Coleopterous fauna of Europe, according to the calculation of 

 M. Lacordaire, there is only one-third. The genera found to-day 

 in both parts of the world have then during the Tertiary epoch 

 played a more important part than is the case now ; hence 

 the knowledge of the character of the fauna is rendered more 

 difficult. We find at Qi^ningen but a ver\^ small numl)er (live) 

 of genera exclusively European ; seventeen are ibund to-day 

 in Europe, in Asia, and in Africa, but not in America. For the 

 most part tliey belong to the Mediterranean launa (comprising 

 eight genera) and give to the insect-fauna of Q^ningen a strong 

 proportion of Mediterranean forms. In this fauna I onl}- know 

 of one exclusively Asiatic genus ; two are peculiar to Africa, 

 and two others {AnopUtes and Naupactus) are American. 



"There are noAV living, however, in Europe certain genen; 

 which, without being exclusively American, since they are found 

 in Asia and in Africa, belong more peculiarly to America ; such 

 are Belostonmm, Hypselonotus, Diplonychns, Evagnrus, /Sten- 

 opoda^ Plecia, Caryborus, and Dineutes. . . . The genera peculiar 

 to our fauna of Tertiary insects amonnt to forty-four, of wliich 

 twenty-one belong to the Coleoptera ; among the Orthoptera 

 there is one, and six Hymenoptera, six Diptera, and eleven 

 Hemiptcra. They comprise 140 species." (Heer.) 



An apparently still richer locality for Tertiary insects has 

 lieen discovered by Professor Denton west of the Rocky IMoun- 

 tains, near the junction of the White and Green Rivers, Colo- 

 rado. According to Mr. Scudder "between sixty and seventy 

 species of insects were brought home, representing nearly all 

 the ditierent suborders ; about two-thirds of the species were 

 Flies, — some of them the perfect insect, others the maggot-like 

 larvae, — but, in no instance, did both imago and larva of the 

 same insect occur. The greater part of the beetles were quite 

 small ; there were three or four kinds of Homoptera (allied to 

 the tree-hoppers), Ants of two different genera, and a poorly 

 preserved Moth. Perhaps a minute Tlirij^s, belonging to a 

 group which has never been found fossil in any part of the 

 world, is of the greatest interest." 



He thus sums up what is known of American fossil insects. 



