SOME ADDITIONS TO THE CARBONIFEROUS TER- 

 RESTRIAL ARTHROPOD FAUNA OF ILLINOIS. 



Insect remains of Paleozoic age, representing the advent of 

 a class of organisms which is today the largest and most highly 

 specialized of all animal groups, naturally possess an absorbing 

 interest. Unfortunately but few localities have been discovered 

 that yield these fossils, and these have produced but a small 

 number of forms as compared with those of Tertiary and recent 

 time. From the strata of Silurian and Devonian age, insect- 

 remains are so extremely rare that but little can be asserted of 

 them, the bulk of Paleozoic insects being from strata of Upper 

 Carboniferous age. As might be expected. Paleozoic insects 

 often combine in one individual, characters that at the present 

 time are distributed among several orders, and for these syn- 

 thetic forms which have no living representatives, the name 

 Palseodictyoptera has been proposed by Goldenberg and fol- 

 lowed by Scudder. 



With the exception of two species preserved in the collec- 

 tions of the Chicago Academy of Sciences, all the material 

 described in the present contribution is in the palaeontological 

 collection of the Walker Museum of the University of Chicago, 

 and most of it is from the Gurley collection. With one excep- 

 tion, the specimens are all ironstone concretions, and nearly all 

 are from the famous Mazon creek locality in Grundy county, 

 Illinois. A portion of the collection studied has already been 

 worked over by Dr. S. H. Scudder, and the results of his inves- 

 tigations have been published in a number of his papers, and all 

 that is desired in connection with this portion of the material is 

 to make known the location of the type specimens. Among 

 the remainder of the collection there are several forms of very 

 great interest. 



The new forms here described are all more or less closely 

 allied to those already known from America, and the classi- 

 fication here used is that elaborated by Scudder rather than 



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