92 THOMAS SAY FOUNDATION 



the wings are relatively long with open meshwork of 

 veins. Its nearest ally is Perla modesta, from which it 

 differs in venation by the possession of the crossveins 

 above mentioned, and by a much shorter fusion of veins 

 Rs and M in the hind wing. 



Only one specimen, the female type, from New Mexico, 

 is known; the second specimen (from Colorado) men- 

 tioned by Miss Smith is Perla modesta. 



Perla obscura, new species. 



(Plate 25, fig. 15.) 



Length to wing tips, female, 17 mm. ; expanse, 30 mm. 



Color blackish, with a broad yellow thoracic stripe 

 and yellow tipped abdomen. Head blackish at the sides, 

 and across the middle ocellus where the color is deepest. 

 There is a long yellow inverted-mushroom-shaped spot on 

 frons and clypeus. A broader yellow spot covers the rear 

 of the head, rounded in front where it fills the ocellar 

 triangle, widened in small lobes behind the rear ocelli, 

 and again upon the occipital border. Rear ocelli equidis- 

 tant from the eyes and from each other; middle ocellus a 

 little smaller than the others. Antennae and palpi black- 

 ish. 



Prothorax a little wider than long, a very little nar- 

 rowed to rearward, sharp angled, very faintly and dif- 

 fusely embossed upon the black sides of the disc. Median 

 yellow stripe bright yellow, parallel sided, ragged edged. 

 This stripe terminates in a triangular spot on the meso- 

 thoracic praescutum, lateral to which is a pair of smaller 

 pale spots. Legs blackish with an obscure wash of yel- 

 lowish on the femora just before the knees. Wings 

 flavescent-hyaline, especially in the disc and along the 

 costa, with brown veins, and rather copious venation, the 

 median vein being three-branched. 



Abdomen blackish except for a yellow tip, and tails 

 blackish. 



Male unknown. 



Female. Yellow on abdominal segments 9 and 10 and 

 the extreme base of the tails and the sternum of 8 at the 

 sides of the blackish subgenital plate. The latter is ovate, 

 evenly rounded, and almost reaches the apex of the 9th 

 sternum. 



This species is close to the preceding, agreeing in gen- 

 eral type of coloration and venation. It can hardly be 

 the same species, for it is too small, details of coloration 

 are different, the tip of the fore wing is shorter and the 



