ARTHROPOD A— INSECTA. 



A17 



serially from one stem backwards, or it forms two compound 

 main branches, or (more rarely) the offshoots are directed for- 

 ward; Cu with a variable number of veinlets, branching off pos- 

 teriorly; anal area chiefly rather large, its veins never or quite 

 exceptionally ending in the anal fold, but generally in the pos- 

 terior border. Examples: Hemimylacris clintoniana Scudder (Fig. 

 1738,0), from the Cherokee shales of Missouri, Orthomylacris 

 antiqua (Scudder) (Fig. 1740, &), from Mazon Creek, 111.; and 

 Mylacris anthracophila Scudder (Figs. 1740, a; 1741), from the 

 Alleghany of Colchester, 111. 



Of the remaining families of the Palaeozoic Blattoidea, the ma- 

 jority are represented in North America, but generally only by a 

 few species. 



Order HADENTOMOIDEA Handlirsch. 



This order is represented by only one species Hadentomum 

 americanum Handl. (Fig. 1742), from the Kittanning horizon 















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Fig. 1742. HadentomujH americamim Handl., Mazon Creek, III. Carbonic. A 

 nearly entire individual and hind and fore wings. ( C, costa ; Sc^ subcosta ; /\', 

 radius ; /'j, radial sector; M, media ; Cu, cubitus ; A, anal area. (After Handlirsch). 



of Mazon Creek, 111. It has a large head, very elongate prothorax, 

 and rather simply veined wings. R simple, the radial sector three- 

 branched, and arising near the base ; M forked once, Cu with four 



