22 
Psyche 
[March - June 
tion is typical of that of the tribe Stenonemiini, as shown in text 
figure i, with the exception of the presence of the numerous branches 
of the radial sector. The hind wing, which is about one and one-half 
times the length of the fore wing, has a slender petiole and terminates 
in two conspicuous dilations. The distal dilation appears to be at the 
termination of the wing; there does not seem to be a terminal exten- 
sion, tapering more nearly to a point, as Navas indicated by dotted 
lines in his figure 4 (1913). The two dilations are almost certainly 
somewhat twisted as the fossil is preserved ; this, of course, is what 
one would expect from the condition of the hind wing as it occurs in 
most living specimens of the family. The petiole of the wing is hyaline, 
but the two dilations are almost solidly dark in color, although there 
is an indication of a small hyaline area in the region of the twisting; 
this light area could, of course, be due to peculiarities of preservation, 
although the two light areas are in the same position in both of the 
hind wings. 
Holotype: This consists of a nearly complete specimen with all four 
wings outstretched (plate 1), with the venation of the front wings 
very clear ; collected in the Florissant shales, Colorado ; 4 deposited in 
the Department of Palaeontology, British Museum (Natural His- 
tory). 
The species which Pierce and Kirkby described (1959) from Oli- 
gocene shales in Montana as Olivierina metzeli is apparently closely 
related to americana and may in fact be that species. The size of the 
insect is virtually identical with that of americana. Unfortunately, 
the specimen on which the metzeli is based is poorly preserved; the 
venation of the fore wing is not discernible, and the form of the hind 
wing is not clearly shown. The authors state that the dilated part of 
the hind wing narrows for a short distance and widens again to a 
narrow inflation. Mrs. Kirkby informs me that, though the 
apical portion is not complete in the type specimen, there is enough 
evidence preserved to show that the “paddle” widens again. Pierce 
and Kirkby apparently incorrectly interpreted Cockerell’s description 
of his americana and they were unaware of Navas’ published redescrip- 
tion of americana and of his establishment of the genus Marquettia. 
In his account of americana , Cockerell stated that the black area of 
4 Formerly thought to be of Miocene age but now usually considered Oligo- 
cene. 
Explanation of Plate 1 
Marquettia americana (Cock.). Photograph of holotype [Courtesy of 
British Museum (Natural History)]. 
