22 SCTJDDER ON THE DEVONIAN 



by comparison of what we have presumed to be similar parts, we may suppose this wing 

 to have been slightly larger than that of Homothetus fossilis, and its probable length not 

 far from 50 mm. 



Whatever views are held of the special homologies of the veins, its right to generic dis- 

 tinction from Homothetus, to which it is most closely allied, must be conceded on the 

 ground of the greater simplicity of the neuration. 



On account of the insignificance of the fragment, however, and the consequent impos- 

 sibility of any sure clue to its affinities, it would not have been worth while to confer 

 upon this wing a distinctive generic name, even granting its generic dissociation from all 

 others, were it not for the extreme interest attaching to any insect fragment of such high 

 antiquity. 



The remains were found in plant bed No. 8, of Professor Hartt, the highest in the Lan- 

 caster series. 



VII. LiTHENTOMUM HaRTTII. PI. 1, fig. 3. 



Lithentomum Harttii Scudd., Can. nat. geol., (n. s.) in., 206, fig. 4 (1867); — Ib., 

 Geol. mag., iv, 387, pi. 17, fig. 4 (1867) ; Ib., Daws., Acad, geol., 2d ed., 525, fig. 183 

 (1868) ; — Ib., Amer. nat., i, 630, pi. 16, fig. 5 IHartii] (1868); — Ib., Geol. mag. v, 172, 

 176 (1868); — Pack., Guide ins., 77, 78, pi. 1, fig. 5 (1869). 



Mentioned without name, as the third species, in my letter to Professor Hartt : On the 

 devonian insects of New Brunswick, p. 1; Bailey, Obs. geol. south. New Br., 140 ; Amer. 

 journ. sc, (2) xxxis, 357 ; Can. nat. geol., (n. s.) ii, 235 ; Trans, ent. soc. Lond., (3) 

 II, 117 — all in 1865. 



The relic to which this name has been given is the central upper portion of a wing in a 

 very fragmentary condition, but with a bit of the upper margin sufficient to enable one 

 to determine pretty positively the homologies of the veins. A fragment of Calamites has 

 unfortunately covered the base and lower part of the wing, but one or two of the veins 

 appear through it at what must be the very base of the wing, and help to determine its 

 nature. The fragment preserved is 36 mm. long, and 15.5 mm. broad; but the wing was 

 probably 55 mm. long, and perhaps 20 mm. broad, if one may judge from its general 

 appearance only ; it certainly represents a large insect. 



The marginal vein forms the border. The mediastinal vein in the basal half of the 

 wing, and probably for some distance beyond, runs parallel to and at considerable dis- 

 tance from the border, with which it is connected by very weak oblique cross veins at 

 irregular intervals, which toward the base are considerably more oblique than further 

 outward ; this weak construction of the costal margin renders it probable that the wing 

 was a hind one. The scapular vein in the Ixisal quarter of the wing runs in very close 

 proximity to the mediastinal, then parts from it a little, and continues sub-parallel 

 to it, but a little nearer to it than the latter to the border ; there appear to be no cross 

 nervules between these veins, but a slight and irregular tortuous longitudinal line like 

 a mere puckering of the membrane ; at some distance before the middle of the wing 

 this vein puts forth at a slight angle an inferior liranch, which takes an arcuate course 

 sub-parallel to the vein, and is forked about as far beyond the middle of the wing, 

 apparently, as it arose anterior to it, both offshoots taking a longitudinal direction. 



