156 BRITISH APHIDES. 



Recent researches have proved that both the 

 Heteropterous and Homopterous Hemiptera, includ- 

 ing Aphidida?, are well represented in North America 

 by fossil remains. Many specimens have been obtained 

 from the districts of White River in Utah, and of 

 Green River Station in Wyoming. 



The remarkable lacustrine beds of Florissant, in 

 Colorado, arc now undergoing a thorough examination 

 by Mr. S. H. Scudder, who has already thrown so much 

 new light on fossil insects. The last gentleman gathers 

 from the description of the fauna and flora (which is 

 very abundant) that the remains belong to later Miocene 

 time, and therefore they may prove interesting as sup- 

 plementing Prof. Heer's labour in Europe. 



Mr. S. H. Scudder kindly enables me to reproduce 

 several of his fine figures of Aphides — figures which 

 are prepared to illustrate his works on the Fossil 

 Insects of North America, in connection with the 

 Geological Survey of the United States. 



These plates have not yet been published, but I 

 have his permission to use them, and some figures are 

 redrawn in PL CXXXIII, Vol. iv, of this Monograph. 



The ancient lake at Florissant is situated high up 

 in the mountains on the southern slopes of the 

 Colorado Range. The existing basin is about five 

 miles in diameter, but several creeks in former times 

 ran up from the shallow water into the neighbouring 

 valleys. 



These Tertiary beds form the bottom of a basin 

 which overlies the granite. Here and there this rock 

 protrudes from the flat in the form of islets. The 

 superincumbent beds comprise conglomerates and 

 variously coloured sandstones, interposed with deposits 

 of fine smooth, argillaceous material, well suited to the 

 preservation of leaves and insects. 



Below these beds, black, brown, and whitish-drab 

 shales occur, containing large masses of opalised 

 wood, probably the remnants of ancient Sequoia-. 

 Some of the stems still remain in the positions in 



