90 Annals Entomological Society of America [Vol. V, 
was quickly severed with a razor together with a portion of the 
thorax, in order to preserve the connection between the wing 
and body trachea. The wing was then placed upon a moist- 
ened slide and a cover glass bearing a little melted glycerine 
jelly was laid over it. The preparation was immediately 
cooled upon a slab of iron. It was examined as soon as the 
glycerine jelly hardened, and a camera lucida sketch or photo- 
graph was made. All of the figures here presented were secured 
by the latter method. From five to ten preparations of each 
form were photographed. Blue prints were made from the 
negatives. The outlines of the trachee and veins were then 
traced directly upon the print. Later the blue color of the paper 
was bleached out with a saturated solution of potassium oxalate. 
The ink drawing left upon the white field was then used directly 
for reproduction. 
Historical. 
The most important discussions of May-fly wing venation 
are contained in the following works. 
EATON ’83 (Revis. Monog. Ephem. ’83) divided the veins of 
the May-fly wing into three groups to which he applied a series 
of names and numbers as given in the following table. The 
first group consisted of the longitudinal veins 1 (costa), 2 (sub- 
costa), and 3 (radius), which are all connected by the great 
cross vein. The second group consisted of veins 4 (sector), 5 
(cubitus), 6 (praebrachial) and 7 (pobrachial). The third 
group consisted of the anal and axillary veins. He called atten- 
tion to the tendency of the hinder groups to secede from their 
own set and to annex themselves to the hinder branches of the 
group next in advance. 
REDTENBACHER ’86 used Eaton’s system but altered it so 
that it would agree with the theory of convex and concave 
veins, proposed by Adolph, which Redtenbacher had unfor- 
tunately adopted. The May-fly wing was considered to be a 
very generalized type. Redtenbacher emphasized the relation- 
ship between May-flies and dragon-flies, stating that though 
transitional forms are lacking the wings of the two are so like as 
to be easily ascribed to a common origin. 
Comstock ’88 adopted Eaton’s system using the same 
grouping and homologies. He used names instead of numerals 
in labelling the veins. 
