suBPHYLüM III INSECTA 821 



of various primitive groiips are known froni tlie Perniiaii of Riissia, Germany, West 

 Virginia, Kansas and Colorado, so that on tlie wliole we are fairly well acquainted 

 with these heterometabolic ancestors of modern Orders. Unfortunately, liowever, very 

 little evidence is fortlicoming from the Trias, during whicli era the transition from 

 tlie lieterometabolic to the holometabolic stage probably took place. Nevertheless, 

 a few fossil remains are known from tlie Trias of Sweden, Germany, Austria, 

 Switzerland and China. Niimerous tracks of supposed Insects, and also what are 

 believed to be the aquatic larvae of an alder-fly {Mormolucoides articulatus Hitchcock), 

 occiir in the dark shales of the Connecticnt Valley Trias. 



A fairly rieh insect fauna has Ijeen discovered in the Lias of Schambelen in 

 Aargau, Switzerland, Dobbertin in Mecklenburg, Brunswick, Weyer in Austria, and 

 several localities in Somerset, Gloucestershire and Yorkshire, England. A few 

 remains are preserved in the Stonesfield Slate near Oxford, England, and in strata 

 of the same age in Siberia ; and a considerable number of species occurs in the Purbeck 

 of the southwestern counties of England. Eichest of all, however, is the Upper 

 Jurassic insect fauna, especially that which is found in the Lithographie Stoiie 

 (Kimmeridgian) of Bavaria. Contrariwise, the ^Cretacegus is markedly deficient in 

 Information respecting this group of invertebrates. 



Tertiary Sediments have yielded an enormous quantity of well-preserved insect 

 remains. Aniong the more important localities that have furnished material of this 

 nature, mostly of mid-Tertiary age, may be mentioned the freshwater deposits of 

 Florissant, Colorado, Aix-en- Provence, Oeningen on Lake Constance in Baden, Radoboj 

 in Croatia, Eott (Upper Oligocene lignite) near Bonn on the Rhine, Brunnstatt in 

 Alsace, Sieblos in Bavaria, Bilin in Bohemia and Gabbro in Tuscany ; also the 

 Oligocene strata at Quesnel in British Columbia, and the Green River Eocene of 

 Wyoming, western Colorado and eastern Utah. But by far the largest and itiost 

 varied assemblage of Tertiary insect remains is obtained from Oligocene amber in 

 East Prussia. 



Finally, in the Pleistocene, the interglacial clays of Switzerland, Germany and 

 Ontario, the peats of northern France and England, the ozokerite of Galicia, and the 

 lignites of Hösbach in Bavaria, deserve mention as localities which .have furnished 

 fossil insect remains. In the accompanyiiig table is indicated the geological ränge of 

 the different orders of Insects. 



[The preceding chapter on Insecta has been prepared especially for the present work by 

 Professor Anton Handlirscli, of the Imperial Museum of Natural History at Vienna. A 

 few minor eniendations have been suggested by Dr. W. J. Holland, Director of the Carnegie 

 Museum at Pittsburgh, and otliers by Professor T. D. A. Cockerell, of the University of 

 Colorado. — Editor,] 



