LUCY WRIGHT SMITH 
479 
and tip of tarsi, ringed with dark browTi. Wings with fine yellowish-brown 
venation, an irregular network of cross-veins occupying the tip of the wing in 
the region between radius and the anterior branches of the sector; a little less 
than the first half of the costal area beyond the humeral cross-vein free from 
cross-veins; subcosta runs into radius beyond the level of the cord; the length 
of the inner inter-radial cell twice as great as its base (fig. 63). 
Both long and short winged males, in the latter the wings are not greatly 
shortened, they extend to the tip of the abdomen. Five pairs of long, white, 
slender, fleshy, finger-like, tracheal gills arranged as follows; one pair widely 
separated on the base of the submentum, a second pair on a line with the first 
in the articulation between head and thorax, the third pair a little lateral and 
anterior to the base of the fore legs, the fourth pair on the anterior border of 
the mesothorax on a line with the base of the legs, and the last pair in the 
same relative position on the metathorax. 
Male. Abdomen dark brown above and on the sides, pale on the venter. 
Setae about three-fourths the length of the body; pale brown, conspicuously 
ringed with darker and provided w'ith whorls of fine bristle-like hairs toward 
the tip of the segments. The seventh dorsal segment triangularly produced 
over the eighth, and ending in a strong, upright median fork; the eighth seg- 
ment, normal; the ninth entire, narrow above, elongated below into a con- 
spicuous subgenital plate marked with fine transverse striae, a median villous 
area set off from the lateral parts by prominent carinae. The tenth segment 
concealed by the ninth on the venter; widely cleft above, each lobe with an 
erect appendage-like process on the inner posterior margin; sub-anal plates 
boat-shaped, flaring; stylets entirely concealed by the para-genitals which 
appear between the posterior border of the tenth tergite and the sub-anals, 
as a pair of lateral chitinous sheaths with a white, membranous median portion 
(fi^. 51). 
In the entomological collection at Cornell University there are 
three male specimens, two (alcoholic) from San Diego, California, 
IV, 23, 1879, and one from Nevada County, California (C. V. 
Riley collector). One of the specimens from San Diego is the 
type of this species. 
Female unknown. 
Nymph unknown. 
Arcynopteryx ignota new species 
Adult 
9 . — Length to tip of wings, 17 mm.; expanse of wings, 29 mm.; length of 
setae, over 11 mm. (those on the specimen measure 11 mm. but they are 
broken). 
Dark brown, with a few paler markings. Head triangularly produced; three 
moderately large ocelli arranged in an isosceles triangle, the base of which is 
greater than the sides, but less than the distance from the posterior ocelli to 
the inner margin of the eyes; the M-shaped mark present but not prominent, 
TRANS. AM. ENT. SOC., XLIII. 
