OCTOGOMPHUS 121 
green triangle between them below the crest. Stripe 4 broadly interrupted above 
the spiracle. Stripe 5 continuous. Legs black. Wings hyaline with brownish 
stigma. The yellow middorsal line of the abdomen narrows on 3, disappears 
on 4, and the posterior part of the abdomen including the appendages is black. 
The nymphs of this species (Ndm. ’01, p. 442) frequent the sandy beds 
in the deeper parts of small spring brooks. They dig rapidly. They 
feign death for a few minutes when taken from the water. 
13. OctrocomPHus Selys 
These are elegant little black and yellow Gomphines that are easily 
recognized by the broad yellow patch that almost covers the front of 
the thorax (stripe 1 being wanting) and that has the shape of an in- 
verted urn. In venation they resemble Lanthus, except in the minor 
characters stated in our key to the genera. 
The abdominal appendages of the male terminate in 8 points (whence 
the generic name), the inferior being four-lobed, and the superiors each 
two-lobed, as shown in our figures. 
The sole known species occurs along the mountain streams of our 
Pacific slope. 
The nymphs burrow in the sandy places in the edges of snow-fed 
mountain stream beds or lie amid the loose trashy sediment, whence 
they are easily obtainable by sifting the surface layer. The senior 
author found them associated with larvae of soldier flies (Euparyphus) 
and midges (Chironomous and Tanytarsus) at the edges of the current 
in Cucamonga and other Cajions in the San Gabriel mountains in 
Southern California. A few were found in the sand bars of the Santa 
Ana River, where it meanders over the hot plain. These nymphs, when 
placed in a dish of gravel or sand, quickly buried themselves by digging 
deeply into it. Kept for weeks in a small dish with the big predacious 
nymphs of Cordulegaster, they managed to escape being eaten. They 
are quite agile. They are the cleanest of Gomphine nymphs, as befits 
their dwelling in the clear, cold streams. 
78. Octogomphus specularis Hagen 
Hag. 59, p. 544: Mtk. Cat. p. 101: Kndy ’17, p. 574: Smn. ’26, p. 20. 
Length 50 mm. Expanse 66 mm. Calif. 
A very pretty little Western club-tail with a yellow inverted-urn shaped mark 
covering the front of the thorax, and very broad shoulder stripes of black. Face 
pale cross-lined with black on the sutures, the lower stripe running down on the 
middle of the labrum; the latter is margined with black. Occiput black, with 
yellow hind border. Thoracic stripes of the first pair wanting, so that there is 
a very wide median yellow area. Stripes 2 and 3 unusually broad, often wholly 
