116 



PROCEEDINOS OF THE NATIONAL MUSEUM. 



Tou 46. 



The following tables give the variations in the venation of the wings 

 of the males: 



By selecting from each column of the foregoing tables the character 

 held by the greatest number of individuals, the following general 

 description is made up: Male, abdomen 36 mm., hmd wing 30 mm., 

 eight antecubitals and six postcubitals in fore wing, five antecubitals 

 and seven postcubitals in hind wing, one vein in triangle of fore 

 wing, no veins in triangle of hind wing, and three veins in internal 

 triangle of fore wing. It is interesting to note that among the 41 

 males none had this particular combination. 



Color of Somatochlora semicircularis, female, field No. 12. 



Vertex metallic blackish green, finely and evenly punctate and 

 covered with dark pile. Ocelli tan-colored. Antennce black. Frons 

 metallic green, slight!}' lighter in color and more brilliant than 

 vertex, evenly but more coarsely punctate than vertex ; each lateral 

 face with a yellow triangle.^ Clypeus with center yellow, its mngs 

 metallic green, covered with yellow pUe. Labrum black. Labium 

 yellow, coarsely punctate, and covered with yellow pile. Eyes gray. 

 Base of head black, with submarginal row of white hairs. 



Prothorax black, with anterior edge of dorsum yellow, and a 

 diamond-shaped, yello\vish, cushion-like marking at posterior edge. 

 Coxge yellow on external and posterior surfaces, black on internal 

 surface. Legs black. 



General color of mesothorax and metathorax metallic green, with 

 faint yellowish reflections, thickly and evenly covered with long 

 yellow pile. Middorsal carina dark brown. Antealar sinus and 

 ridges yellowish. Mesepimeron with vertical, yellow, oval spot. 

 Metepimeron with faint yellow, oval spot. (Some females do not 

 show this second yellow spot.) Wings hyaline, except brown stigma, 

 a yellow tinge at base of wings, and opaque membranules. 



Abdomen black, with a faint greenish luster, except as follows: 



Segment L Side with a vertical, elliptical spot of buff -yellow. 



I See footnote, p. 114. 



