CALVERT: MACROTHEMIS AND ITS ALLIES. 
309 
eric characters of the other three are to be compared with the corre¬ 
sponding characters of these tAvo, and by such a method the diagram 
has been drawn up. 
The preceding statistics of variation may also furnish some evi¬ 
dence— of rather, negative kind it must be confessed — on the 
question of the relative stability or variability of the two sexes. 
Specific Details. 
1. Dythemis Hagen. 
Hagen, Syn. Neur. N. Amer., p. 162, 1861. Calvert, Proc. Cal. 
acad. sci., (2), vol. 4, p. 522, 1895 (with synopsis of North Ameri¬ 
can species). 1 
§ I. Wings colored at the base or apex or both. Anterior lamina 
of J less prominent than genital lobe. 
1. D. fugax Hagen. PI. 1, hors. 6, 7. Hagen, Syn. Neur. 
N. Amer., p. 163, 1861. 
This species, with velox, has undergone the least modifications in 
the femoral armature of the males. The antero-infenor i*oav of 
teeth on the second femora consists of 10-15 teeth on the basal half, 
7-8 spines on the apical half; on the third femora of 20-26 serra¬ 
tions, 6-10 spines; these are in all cases directed towards the knee. 
See plate 1, figs. 6 and 7. 
Distribution. Texas : Pecos River, Waco, Carrizos Springs in 
Dimmit Co., Round Mountain in Blanco Co. (Schaupp). July, 
August. (Hagen, 1875, Coll. P. P. C.) 
2. D. velox Hagen. Hagen, Syn. Neur. N. Amer., p. 163, 1861. 
In the synopsis of species quoted above (Calvert, 1895) the frons 
and vertex of velox are stated to be “yellowish-green to brown.” 
An examination of Hagen’s types shows variation, possibly due to 
age-differences, from pale green and luteous through brown to 
metallic blue. This diminishes still more the differences supposed 
to separate velox from sterilis. I tabulated the various color pecul¬ 
iarities of individuals related to these tAvo forms (there seem to be 
no structural differences), contained in the Museum at Cambridge 
and in my oavii collection, and have thus brought together a 
1 Full bibliographical references are not given in this paper when one of those quoted 
already contains a full list. 
