204 TERTIARY INSECTS OF NORTH AMERICA. 



according more closely with Forficula than with Labidura. But one point 

 after another showed such distinction from Forficula that the species seem 

 more correctly presented when placed in a distinct genus. Whether all 

 belong there is perhaps questionable, especially when the extreme members 

 of the genus are compared. Moreover, all the characters upon which the 

 genus is founded are not to be found in all the species here described, as 

 preserved in the specimens at hand ; but in the order in which I have 

 arranged them they show such a gradual passage from one to the other 

 that notwithstanding the diversity in general aspect and in size between 

 the first and the last, I can find no good characters in their imperfectly 

 preserved structure by which they should be separated. The genus is 

 without doubt nearly allied to Forficula, but it is impossible to place it 

 there, or indeed in any known existing genus of Forficularire on account 

 of the great size of the eyes. These are not only as large in front as in 

 Cylindrogaster and Sphongophora, but instead of being shut off from the 

 posterior half of the head, as in all living Forficularise known to me, they 

 extend to the posterior margin, as may be readily seen in Figs. 3 and 12 of 

 PI. 16; that is, instead of being anterior they are lateral. The genus is 

 also peculiar for the great simplicity of the forceps, which are long and 

 rather (sometimes very) slender, and, with a single exception, where there 

 is one basal tooth, they are entirely unarmed. The antenna;, where they 

 are preserved, show some diversity of structure and it is partly on that 

 account that I have hesitated about keeping them together; but as a general 

 rule they are comparatively short, not extending backward beyond the 

 closed tegmina, rather coarse, the joints about as numerous as in Forficula, 

 the basal joint not very long nor stout, the joints in general shorter compared 

 to their width than in Forficula, All the species, with perhaps one excep- 

 tion, are winged, and all have tegmina of the normal form. It is not a little 

 curious that several specimens have the wings fully expanded, and these 

 show in all their main features the same characteristics as the strangely 

 folded wings of earwigs to-day, showing that the type was fully developed 

 in this early Tertiary period. One may notice, indeed, a slightly greater 

 simplicity of structure here and both greater simplicity and greater 

 uniformity of character in the forceps of the fossil species, which seem 

 to betoken an approach toward the origin of the type, but it is a mere sug- 

 gestion, or scarcely more than that 



