1976] 
Kukalova-Peck and Peck — Calvertiellidae 
87 
Moravia convergens Kukalova, subimago 
Figs. 1,4B, 7 
Occurrence: Lower Permian (Upper Autunian) of Obora, Czechoslovakia. 
Original: Specimen no. 2/ 1976 (obverse and reverse), deposited in the Paleontologi- 
cal Institute of Charles University, Prague, Czechoslovakia. 
The fore wing has venation identical to that of the adult (Kuka- 
lova, 1964, fig. 2) (fig. 4 A), as well as almost identical dimensions 
(length 36 mm, width 15 mm). The subimaginal characters known 
in Recent mayflies, such as the opaque wing membrane and mar- 
ginal hairs, could not be observed because they would be lost in the 
fossilization process. The subimago is distinguished from the adult 
by the latero-posteriorly curved wing tip. Thus, if the proximal 
part of the wing axis is set parallel to that of the adult fore wing, the 
entire anterior margin of the subimago appears to be much more 
convexly curved (fig. 1). However, this position of the wing is not 
natural, since in the living insect the wing axis in subimagoes was 
directed somewhat obliquely backwards as in figs. 4B-C. Because 
of the curved tip, the subadult wings are distinctly narrower in the 
apical part than the adult wings. Otherwise, there is no noticeable 
difference in the pteralia membrane (fig. 7), reticulation, or vena- 
tion which lies outside the range of individual variation (figs. 1, 4). 
The overall similarity in venation and size of the subimaginal and 
adult wings of Moravia convergens is the proof that the develop- 
ment was gradual and marked by only a series of moultings as in 
apterygotes. The number of winged subimagoes was probably more 
than one, judging from data on the related Megasecoptera (Kuka- 
lova-Peck, 1974). 
Carrizopteryx Kukalova-Peck, n. g. 
Type species: Carrizopteryx arroyo, n. sp.. Late Pennsylvanian (Virgilian) of New 
Mexico. The genus is monobasic and founded on the venation of a single hind 
wing. 
Description. Hind wing: membranous, triangular, very broad in 
proximal half; subcostal area small; anterior margin slightly con- 
cave. Postcostal vein short; Sc terminating on R1 at mid-wing; the 
stems of R and M fused; flat, ribbon-like stem of Cu adjoining the 
R+M stem; R, M+CuA and CuP substitute a cuticular thickening 
of other calvertiellids by radiating from a single spot, at about the 
first quarter of the wing length; Rs originating shortly beyond the 
