28 Inuinoris Naturat History Survey BULLETIN 
were observed to leave the sand in the 
bottom, swim about in the water, and, after 
molting, re-bury themselves in the sand. 
KEY TO SUBFAMILIES 
ADULTS 
1. Veins Sc and R, of fore wing curved pos- 
teriorly and continued around apical 
angle of wing; marginal veinlets want- 
ing, fig. 44. Middle and hind legs of 
both male and female completely 
atrophied beyond trochanter, or femur, 
tibia, and tarsus degenerated to mere 
membranous flaps; male forceps un- 
SOPMION TER MRA GOs ccc hes rk Haire ay 
NE ieiietel Re a Campsurinae, p. 28 
Veins Sc and R, of fore wing straight at 
apexes; marginal veinlets present, figs. 
38, 40, 42, 46. Middle and hind legs 
beyond trochanter not atrophied or de- 
generated to membranous _ vestiges; 
male forceps segmented, figs. 61-63, 
BS SOP Ge Re ae are ce eet esfeneinae oer ene 2 
2. Marginal veinlets of fore wing extremely 
numerous; cubital intercalary veins 
straight, not attached at bases to Cu, 
MEAD Bet wi aettinate tes Ephoroninae, p. 32 
Marginal veinlets of fore wing relatively 
few in number; cubital intercalary 
veins sinuate, attached at bases to Cu, 
figs. 405 BG etter auc a 3 
3. First anal vein of fore wing forked near 
Wind Maron HO. 42 ccs ci we hw cee 
SA Neer os ae Potamanthinae, p. 30 
First anal vein of fore wing not forked, 
MAG wale de cee Ephemerinae, p. 35 
Mature Nympus 
Perils; lateral oreo Sie ace oe eae ee eee 
Sap ed i oe Potamanthinae, p. 30 
Gills dorsally Hoga 50 hae a. oes he ce 2 
2. Head without a frontal process......... 
Be ad US onto Campsurinae, p. 28 
Head with a frontal process, figs. 2, 59. .3 
3. Mandibular tusks upcurved 
Se Bay reer rade Ephemerinae, p. 35 
Mandibular tusks downcurved....... : 
PRA Rca aye Ephoroninae, p. 32 
CAM PSURINAE 
The subfamily Campsurinae, as defined 
here, corresponds to the first section of the 
family Polymitarcidae in the classification of 
Ulmer (1933:197). It includes only Tor- 
topus and the very closely related genus 
Campsurus in the Nearctic region. To- 
gether, these two genera include about 50 
species in South America and Central Amer- 
ica, but only 4 species of campsurine may- 
flies have been described or identified from 
America north of Mexico. Of these, 2 
occur in Texas only, another cannot be 
Vol. 26, Art. 1 
identified at present, and the fourth is quite 
generally distributed in eastern North Amer- 
ica. The nymphs are unknown for the 
Nearctic species. 
KEY TO GENERA 
ADULTS 
Middle and hind legs reduced to functionless, 
membranous vestiges, but with all leg-parts 
still discernible..............1. Tortopus 
Middle and hind legs completely aborted be- 
yond the trochanters.......2. Campsurus 
1. TORTOPUS Needham & Murphy 
Tortopus Needham & Murphy (1924:23). 
In the adults, the fore wing has veins C 
and Se recurved around the apical angle of 
the wing, fig. 44; the veinlets along the 
apical wing margin are absent, vein M is 
forked at the wing base, and there are two 
long, cubital intercalary veins. The fore 
leg in the males is developed normally, but 
the middle and hind legs, as well as all of 
the legs in the females, are reduced to small, 
nonfunctional semimembranous _ vestiges, 
which, however, have all leg-parts still dis- 
cernible. The females never molt to the 
imago stage, but mate and lay their eggs as 
subimagoes. In adults of both sexes, gill 
stumps are retained along the lateral mar- 
gins of the abdomen. The median caudal 
filament is vestigial in the males, but is well 
developed in the females. 
It has, unfortunately, not been possible 
as yet to find the nymphs of Tortopus in 
Illinois. ‘The nymphs are presumed to be 
burrowing forms, relatively close in struc- 
ture to the nymphs of Campsurus. Charac- 
teristics for the latter have been given by 
Needam & Murphy (1924:13) and Ulmer 
(19206:17). 
Tortopus primus (McDunnough) 
Campsurus primus McDunnough (1924a:7). 
Campsurus incertus Traver (1935a:286). 
Campsurus manitobensis Ide (1941:155). 
As has been pointed out before (McDun- 
nough 1926:185; Traver 1935a:288), this 
species may be a synonym of Palingenia 
puella Pictet (1843: 145). The type of 
puella has not, so far as is known, been 
located and compared with recently col- 
lected material. Pictet’s description was 
apparently drawn from a single mutilated 
