CLASSIFICATION OP PALEOZOIC INSECTS. 349 



toward the margin at the extremity of its course. The anal vein, starting from the same 

 point, runs parallel to the inner margin throughout its basal curve and as far from it as the 

 mediastinal from the marginal, and after that runs in a straight line to the tip of the sutura 

 clavi, or almost exactly parallel to the inner margin. The margin of the membrane is filled 

 from a quarter to a third its breadth with crowded, parallel, straight veinlets, which appear 

 to arise vaguely from irregularly arborescent interlaced veins originating from the margin of 

 the corium, at subequidistant intervals, which are about equal to those between the oblique 

 branches of the internoinedian vein. The surface of the clavus and corium has a minutely 

 wrinkled appearance, not shown in the figure, formed of faint, crowded, transverse lines ; 

 these are most distinct upon the clavus ; the surface is of a pale brown color, a little irides- 

 cent excepting where along some of the veins it appears to be covered with a clay brown 

 film. The length of the wing is 15.75 mm., and its greatest breadth 5.75 mm. ; a minute 

 fragment of the tip is all that is not preserved. 



It was found in the upper coal measures of Kansas City, Mo., in a small nodule in the 

 blue and bituminuous shales, forming layer 95 of the general section given by Broadhead in 

 Pumpelly's Geological Report, 11, 88-97 (1873), and was received for examination from 

 Mr. R. D. Lacoe under the number 2030. 



The discovery of this fossil in carboniferous beds is a very remarkable one, for up to its 

 discovery not only was no hemipteron known from rocks earlier than the tertiary in Amer- 

 ica, but no heteropterous hemipteron had been found anywhere in paleozoic formations. 

 Yet the structure of the wing shows it to be distinctively heteropterous. The separation of 

 the corium and membrane and the differential character of their structure is as clearly 

 marked, apparently, as in existing types ; the corium, it is true, is usually large in propor- 

 tion to the membrane, and the clavus is very narrow; moreover while unquestionably 

 divided into areas as in modern Heteroptera, their characters are very different. The su- 

 tura clavi for instance, instead of arising far toward the costal margin above the middle of 

 the base of the wing, originates as in most ancient insects considerably below it ; and the 

 clavus, instead of being a broad field of a quadrangular shape (the opposing suturae clavi 

 often forming a secondary triangular projection similar to the scutellum), is a narrow, elon- 

 gated, triangular field of very slight importance and scarcely affecting the shape of the 

 wing, especially as the sutura clavi terminates not before but at the extremity of the 

 corium. Then the membrane, as stated, is very small, somewhat as in Zaitha, and indeed 

 there is no group of Heteroptera to which it can be so well compared as to the aquatic 

 reduvioid subfamily Belostomidae, one of the lowest groups of Heteroptera, though it 

 certainly cannot, be brought within the limits of any existing family. Another striking 

 feature is the basal width of the margino-mediastinal, and mediastino-scapular interspaces, 

 a feature almost or quite unknown in Heteroptera though not so uncommon in the Hoino- 

 ptera. We see, therefore, in the structure of this wing inherent signs of its antiquity — of 

 its alliance to the earliest types of Homoptera and of less degree of divergence from other 

 ancient types. No signs whatever of any approach to an embolium or cuneus are present, 

 showing that in this as in other respects differentiation of the wing had not proceeded very 

 far. Still the actual differentiation into the three grander areas is an indisputable fact 

 which is very surprising; and adds another to the many startling instances already known, 

 where a deep seated difference of structure has appeared abruptly so far as any evidence in 

 wing structure or discovery in the rocks can point out- 





