272 
Psyche 
[June-September 
Figure 7. Protereisma americanum (Demoulin). Photograph of fore and hind 
wing-pads of holotype. The dark veins are convex, the weak ones (hardly visible) are 
concave. Length of fore wing-pad, 5.5 mm. 
the precise correspondence of the heavy (convex) veins of the nym- 
phal wing pad with the convex veins of the adult wing, including the 
intercalary veins of the radial sector and the posterior media. Kuka- 
lova, in her interpretation of the nymphal wings, apparently as¬ 
sumed that all of the heavy veins were the main veins and that all of 
the weak veins were the intercalary veins. As a result, the true MA 
was included in her radial sector, the true MP was termed MA, 
CUA was termed MP, and 1A was termed CUP, etc. In figure 9 I 
include a drawing of the front wing-pad of a nymph (MCZ 8637) 
with the correct interpretation of the venation. A photograph of the 
fore and hind wing-pads of the holotype of americana is in figure 7. 
It is at once obvious from the venation that these nymphs do 
indeed belong to the genus Protereisma. The presence of the deep 
fork and triad on CUA eliminates them from the Misthodotidae, for 
reasons shown below. Demoulin, in removing the nymphs from the 
Ephemeroptera, was clearly misled by Kukalova’s account of their 
venation but his assignment of them to the order Archodonata was 
indefensible. The Archodonata had haustellate mouthparts, where¬ 
as the nymphs had well developed mandibles. Also, the Archodo¬ 
nata lacked the costal brace, as well as the system of triads and 
intercalary veins, so well developed in the nymphs. 3 
3 In my opinion the Archodonata are members of the order Palaeodictyoptera. 
