684 I'ROCEEDIXGS OF THE NATIONAL MUSEUM. vol. xxix. 



LITHE NTOMUM Scudder 

 LITHENTOMUM HARTTII Scudder. 



■ SciDDKH, Devon. In.st'cts, X. J5., lS(io, p. 1. 



Lilliento^iiittii lidrttU Scidder, Caiiad. Xat. (2), III, 1.S67, p. I'OH, pi. iv; Aniiiv. 

 Mem. Boston Soc, 1880, p 22, pi. i, fijr. 8. 



Locality. — St. John, New Brunswick. Little River o'roiip; = 

 ?Pottsville. 



In tliis .small frament of a wing Scudder discovered ""relationship" 

 to the ephenierid.s, enibids, and raphidid.s, and supposed it to be closely 

 allied to the sialids; it was, therefore, to be regarded as the progenitor 

 of this group. On this ground, also, the family " Chronicosialidje " 

 was erected. Hagen supposed the fragment to belong to a true sialid; 

 Brauer, however, again found similarity to orthopteres and homop- 

 teres. Finally Scudder placed the fossil in the " hemeristines," a 

 group of his '"'■ neuropteroid Paheodictyoptera," which, however, as 

 we shall see, contained the most heterogeneous elements. 



DYSCRITUS Scudder. 



DYSCRITUS VETUSTUS Scudder. 



ScuDDEK, Devon. Insectt^, X. B., LS{)n, p. 1. 



Dijscritus vciustus Scudder, Geol. Mag., V, 1868, pp. 172, 17H; Anniv. ^leni. 

 Boston Soc, 1880, p. 20, pi. i, fig. 4. 



Locality. — St. John, New Brunswick. Little River group; = 

 ? Pottsville. 



A small fragment, which neither Scudder nor any other author has 

 been able to classify. 



XENONEURA Scudder. 



XENONEURA ANTIQUORUM Scudder. 



Scudder, Devon. Insects, N. B., 1865, \). 1. 



Xenoneura aniiquorum Scudder, Canad. Nat., n. s., Ill, 1867, p. 206, fig. 5; 

 Anniv. Mem. Boston Soc, 1880, p. 24, j)!. i, figs. 5-7. 



Locality. — St. John, New Brunswick. Little River group; = 

 ? Pottsville. 



This small, poorly preserved remnant of an insect gave rise to the 

 erection of risky In^potheses and called forth a vigorous controversy 

 among authors. A wrinkled place near the base of the wing was 

 interpreted ])y Scudder as an organ of stridulation, and led to the 

 establishment of a distinct family, "Xenoneuridie,'"' which combined 

 the characters of the locustids with those of the neuropteres. Darwin, 

 Dawson, and Packard then made use of this fossil as a ''striking"' 

 example of a synthetical t3^pe and of the earliest appearance of organs 

 of stridulation. Later, Scudder himself was obliged to confess that 



