LIBELLULA. 207 
along anterior margins, deepening in intensity at the base especially 
on the hind wing, where it is most marked in the subcostal and sub- 
median spaces outward to first cross-vein, stigma yellow to brown 
with age, membranule dark grey to black, hind wing with two sub- 
median cross-veins. Abdomen, ¢ 30-82, 2? 275-30; hind wing, 
3 39-438, 9 38-42 mm... . . coe ee - . . 2& foliata. 
CC. Pterostigma long, 5-7 mm.* on front wing; abdomen brilliant red, 
less intense in the female. 
D. Wings somewhat smoky, especially at the apices, usually without 
other colouring, but sometimes smoky yellow throughout and in 
one male (Para) the subcostal and submedian spaces of hind wing 
are slightly fulvous out to first cross-vein; stigma dark brown, 
membranule dark grey to black, hind wing with two or three 
submedian cross-veins; frons of male somewhat flattened supe- 
riorly, sloping forward and downward from the vertex, a pointed 
tubercle on each side where the lateral and anterior surfaces meet. 
Abdomen, ¢ ? , 380-36°5; hind wing, ¢ 87-45, ? 41-51 mm. . 38. herculea. 
DD. Wings yellowish-brown at base for entire width (¢ 2), or only 
as far posteriorly as the submedian space (other ? ? ), and out- 
ward to a varying distance, stigma yellow to red, membranule 
grey, hind wing with one (saturata) or two (croceipennis) 
submedian cross-veins ; frons convex superiorly with the mid- 
longitudinal groove deep, no tubercles. Abdomen, ¢ 29-37°5, 
9 30-35; hind wing, ¢ 35-44, 9 40-45 mm. . 4. saturata and form croceipennis. 
AA. Wings with blackish spots at the nodi, pterostigma moderate, blackish, 
3°5-4 mm. long on front wing, membranule white; hind wing with 
usually one submedian cross-vein. 
E. Wings with a blackish basal streak usually occupying subcostal, median, 
and submedian spaces outward to level of internal or of discoidal 
triangle (front wing), to level of, or even filling, the triangle on hind 
wing; a pruinose patch posterior to this streak, especially on hind 
wing, more marked with age; discoidal triangle of hind wing cross- 
veined ; abdominal segment 8 of female perfoliate. Abdomen, ¢ 30- 
32, 2 28°5-31°5 ; hind wing, ¢ 37°5-41, 9 36-38 mm... . . 5. nodisticta. 
[EE. Wings more or less yellowish along anterior margins, hind wing with 
a triangular black basal spot, veined with yellow, posterior to the sub- 
median vein, extending out to, or filling, the triangle, thence retreating 
obliquely toward, but not reaching, the anal “angle,” the discoidal 
triangle free ; abdominal segment 8 of female not perfoliate. Abdomen, 
3 26-31, ¢ 27-31; hind wing, ¢ 33-36, 9 34-86 mm.. . . . . quadrimaculatat. | 
* Males of saturata type occasionally have the pterostigma only 4:5 mm. long, but there is little danger of 
confusing them with foliata. 
+ This circum-boreal species has been taken at an elevation above 10,000 feet in New Mexico and, 
although not yet recorded from Mexico, will probably be found at high altitudes in the latter country. 
2¢2 
