230 Mr. H. Campion on a 
The figure was noticed by Scudder in 1890 (‘ Tertiary Ins. 
N. Amer.’ pp. 142, 144), who remarked that ‘it appears to 
belong to the subgenus Basizschna, but, as it is certainly 
incorrectly drawn in some particulars, it may be in those, 
such as the simplicity of the subnodal sector [2. ¢., the radial 
sector], upon which this suggestion is based.” 
Goss’s figure is certainly not a good one, but it evidently 
represents a fossil purchased from J. 8. Gardner in 1892, 
and now preserved in the British Museum (Natural History). 
This is likewise a right fore-wing, in almost perfect preserva- 
tion, from the Bagshot Beds of Bournemouth. With it is 
placed the counterpart of the basal half of the fossil, which, 
unlike the main slab, shows the extreme base of the wing. 
For facilities for studying this beautiful fossil, which I 
now proceed to describe, I am indebted to the kindness of 
the Keeper of Geology, British Museum. I am also under 
obligation to Dr. F. Ris, of Rheinau, Switzerland, for valuable 
suggestions respecting relationships with recent genera. 
Trieschna gossi, gen. et sp.n. (PI. XI.) 
Right fore-wing :—Narrow*, entirely hyaline. Apex 
acute. Length about 64mm. Width at its broadest part 
13 mm. Costa strongly arched above the region of the 
triangle. Modus almost exactly at the middle of the wing. 
Distance between nodus and proximal end of pterostigma 
20mm. ‘The antenodal cross-veins very numerous, as many 
as thirty-three being visible; the usual two hypertrophied 
antenodals cannot be detected. Twenty visible postnodals. 
Pterostigma dark brown, broad, 5 mm. long, covering several 
cells ; brace-vein rather slender, very oblique, the anterior end 
not meeting exactly the proximal limit of the pterostigma. 
Subcosta not produced beyond the nodus. No cross-veins in 
the median space. Arculus at the level of the third ante- 
nodal, moderately angulated; the branches of the media 
arising very close together at about the middle. M, slightly 
waved posteriorly before the level of the pterostigma. M,, 
arising well beyond the level of the middle of the pterostigma. 
My arching gently upwards just before the pterostigma, and 
thereafter taking a markedly downward course. Oblique vein 
notrecognizable. Sts bifurcating conspicuously (about § cells) 
before the level of the proximal end of the pterostigma, and not 
arching anteriorly ; fork almost symmetrical ; one row of 
cells between the upper branch and Mg, and four rows of cells 
within the fork at the widest part. KR. suppl. well developed, 
* The principal diagnostic characters are printed in italics, 
