ARTHROPOD A— INSECTA. 



457 



In the neighborhood of 14,000 species occur in the present fauna, 

 while only about 250 Tertiary species are known. The order is 

 first observed in the Lias; about 120 American species are known. 



The plant-lice (Aphididce) 

 occur in the Florissant beds 

 (Schizoneuroides scudderi 

 Buckton, Pterostigma, two 

 species; Siphonophoroides, 

 three species), and the Ful- 

 goridce are also well repre- 

 sented in this formation (Flo- 

 rissantia elegans Scudder, 

 Fulgora obticescens Scudder, etc. ) . This family also occurs in the 

 Green River beds of Wyoming (Oliarites terrentulus (Scudder) ; 

 Lystra, two species; Fulgora, two species; Lithopsis fimbriata 

 Scudder, etc.) and the White River of Colorado (Aphana atava 

 Scudder, Delphax senilis Scudder, etc.). The Jassidce likewise oc- 

 cur in the Tertiaries of Utah, Wyoming, British Columbia and 

 Florissant, Colorado {Acocephalus, two species; Tettigonia, four 

 species, etc.). The harvest-flies (Cercopidce and Cicadidce) are well 

 represented at Florissant. Examples: Cicada grandiosa Scudder 

 (Fig. 1764), Aphrophora, Petrolystra gigantea Scudder, etc. 



Fig. 1764. Cicada grandiosa^ hind wing, 

 X f • Oligocenic of Florissant, Col. (After 

 Scudder.) 



