1987] 
Car pen ter — Fam ily Syntonopteridae 
387 
Palaeodictyoptera might have been derived from the order Ephem- 
eroptera. These ideas, however, were suggested before it was 
generally known that the Palaeodictyoptera had long, haustellate 
beaks. That had actually been shown by Laurentiaux in 1952, but 
there was some delay before its significance was fully appreciated. 
The following year, Laurentiaux (1953) designated a new order, 
Syntonopterodea, for the family. He did not, however, indicate any 
characters that would separate the new order from all others. More 
recently, Kukalova-Peck (1983) has placed the family Syntonopte- 
ridae in the order Ephemeroptera. In my opinion, we do not yet 
know enough about the body structure of the Syntonopteridae, in- 
cluding the mouth-parts and the terminal appendages of the 
abdomen, to justify that decision. As pointed out by Edmunds and 
Traver (1954), the Syntonopteridae may prove to have had two cerci 
plus a median caudal filament like the Ephemeroptera, when 
sufficiently well-preserved specimens are found. In that case, and 
provided they do not have haustellate mouthparts, their assignment 
to the Ephemeroptera would be justified. Until then, I prefer to 
place the Syntonopteridae in the category of Palaeoptera, Order 
Uncertain. 
Literature Cited 
Carpenter, F. M. 
1938. Two Carboniferous insects from the vicinity of Mazon Creek, Illinois: 
American Journal of Science, ser. 5, 36: 445-452, text-fig. 1-3. 
1944. Carboniferous insects from the vicinity of Mazon Creek. Illinois: Illinois 
State Museum, Scientific Papers, 3 (1): 1-20, text-fig. 1-4, pi. 1-4. 
Edmunds, G. F., Jr. and Traver 
1954. The flight mechanics and evolution of wings of Ephemeroptera, with 
notes on the archetype insect wing: Journal of the Washington Academy 
of Sciences, 44 : 390-400. 
Handlirsch, Anton 
1911. New Paleozoic insects from the vicinity of Mazon Creek, Illinois: Amer- 
ican Journal of Science, ser. 4, 31: 297-326, text-fig. 
1925. Palaontologie, in Schroder (ed.), Handbuch der Entomologie, 3, 
118-306, text-fig. 52-237. Fisher (Jena). 
Hubbard, M. D. and J. KukalovA-Peck. 
1980. Permian mayfly nymphs: new taxa and systematic characters, in Advan- 
ces in Ephemeroptera biology (Flannagan and Marshall, ed.) pp. 19-31, 
text-fig. 1-3. 
