NO. 1441. AMERICAN rALEOZOKJ INSECTS— HANDLIRSCH. 668 



REVISION OF AMERICAN PALEOZOIC INSECTS. 



Tliroui^li the lono-c-ontimuHl iictivit}' of Dr. S. H. Scudder a gvoiit 

 tuiiui)('r of forms of fossil insects from the American Paleozoic rocks 

 ha\ (' hecomc kn<nvn to us, and interest in this branch of palec^ntolouv 

 lias thus ])0(?\\ widely increased. As a result, new collections of these 

 organisms, which have furnished valuable material for study, have 

 been secured from many sources. A laru'e share of these new speci- 

 mens is in the possession of the U. S. National Museum, and to me 

 has been intrusted the working up of this collection. This unusual 

 privilege has placinl me under the greatest obligations, since without 

 the investigation of this valuable material it would have been hardly 

 possible to complete in a satisfactory manner my general studies on the 

 paleontology and phylogeny of insects. 



Several ^ears of research have furnished me proof that Scudder's 

 classification required a thorough revision, because his groups include 

 maiidy quite heterogeneous elements and morphologically are not 

 founded on sufficiently broad lines. Hence, the paleontology of 

 ins(M'ts, in a wider sense, could not be previously employed in phylo- 

 genetic conclusions. 



If I have now succeeded in rightly interpreting various errors, and 

 have obtained a more exact description of forms and a sharper delim- 

 itation of groups, I am indebted not only to the abundance and rich- 

 ness of the existing European and American material, but especially 

 to the progress which has been recently made in the domain of insect 

 morphology, and particularly to the fundamental investigations of 

 Comstock and Needham on the venation of the wings of insects. As 

 a result of these studi(\s, the establishment of homologies seems to be 

 divested of its greatest difficulties. 



I can not close this introduction without acknowledging my deepest 

 obligations to the administration of the U. 8. National Museum, as well 

 as to Prof. Charles Schuchert, now of Yale University Museum, but 

 formerly assistant curator, division of stratigraphic paleontology in 

 the National Museum, and to Messrs. David White and L. E. Daniels, 

 not onlv for the magnilicent collections ])laced at my disposal, but 

 also for valuable aid and advice. 



Mr. David White has had the kindness to prepare the following- 

 comprehensive statement of the geological relations of the American 

 Paleozoic, as far as the insect-bearing deposits are concerned. \\\t\\ 

 these data at hand, the relative age of individual forms can now be 

 much more accurately determined and compared with European 

 discoveries. 



