In prophalangopsids the antennal sockets are about midway between the top of the head and the epistomal suture. The hind femur is short, extending no more than 3 mm beyond the end of the abdomen. The hind tibiae are armed dorsally with 8 or fewer spines in each of two rows. The forewings of the male cover half or more of abdomen; those of the female are tiny. Length 17-30 mm.
Identification of species
The three North American species are northwestern in distribution and belong to the genus Cyphoderris. The male subgenital plates of C. monstros and strepitans (great and sagebrush grigs) have a prominent, ventrally directed process lacking in C. buckelli (Buckell's grig). In C. monstrosa the process is shaped like the nail-pulling claw of a hammer; in C. strepitans it is simple and never terminally cleft. Cyphoderris buckelli and C. monstrosa, the two species that overlap in their geographical distributions, can be distinguished by the pulse rates in their calling songs. At every temperature, C. monstrosa has the higher pulse rate.
Humped-winged grigs are found in coniferous forests; C. strepitans also occurs in high altitude sagebrush. Daylight hours are spent in burrows and individuals are sometimes collected by turning stones. At night, males produce a succession of short musical trills at wing-stroke rates of 50-75 (at 25 C) and a carrier frequency of about 13 kHz. The songs of C. strepitans and C. buckelli are indistinguishable, but the geographical ranges of the two species do not overlap. The right and left forewings of males have equally developed files and scrapers. Either the left or right wing may be uppermost at rest and the two positions occur at approximately equal frequencies (Spooner 1973). The extent to which individual males switch between using the left and right files has not been established. The firmest published evidence of "switch-wing stridulation" is the song of a male C. monstrosa while courting a female (Morris & Gwynne 1978). In this song two pulse types were alternated without break. During mating, the female feeds on the fleshy hind wings of the male (Morris et al. 1989).
The Prophalangopsidae include only three extant genera: the North American genus Cyphoderris and two Asian genera that are known from fewer than ten specimens from northern India, Tibet, Afghanistan, and extreme eastern USSR. On the other hand, there are many fossil genera of Prophalangopsidae and the related family Haglidae. F.E. Zeuner (1939) recognized 12 fossil genera older than 135 million years and occurring in England, Germany, Turkestan, and South America.
The term grig is a little-used English word for all jumping orthopterans. It is used here (instead of katydid) to emphasize that the split between the Prophalangopsidae and their closest living relatives, the Tettigoniidae, occurred more than 230 million years ago in Permian times (Sharov 1971).