210 



Usinger: Hemiptera 



Distribution. — Nerthra is a world-wide genus, though 

 confined to tropical and warmer temperate regions. 

 In California N . martini is known only from the south. 

 It also occurs in adjacent parts of Nevada and extends 

 southward to the tip of Lower California. N. usingeri 

 is known only from the type locality, a small wash 

 which empties into the Colorado River near Parker 

 Dam. 



The genus Gelastocoris is exclusively American 

 and our commonest species, oculatus, formerly known 

 in the West as G. variegatus, is distributed throughout 

 the entire United States and southward as well. G. 

 rotundatus is a Central American species which 

 extends northward into Arizona and California along 

 the Colorado River drainage (Adams and MacNeill, 

 1951). 



Taxonomy. — The taxonomy of the genus Gelastocoris 

 has been hopelessly confused because of the unusual 

 variation in color and, to some extent, in size and 

 in other details of external structure. Melin (1928) 

 added to this confusion by describing several species 

 on the basis of superficial characters. His G. califor- 

 iensis cannot be recognized as distinct from oculatus. 

 Martin (1928) made a sound contribution to the taxon- 

 omy of the group, evaluating the various characters 

 and illustrating the male genitalia. Unfortunately, no 

 key was given. At present, then, two species are 

 known from California and these are readily distin- 

 guished by the shape of the lateral margins of the 

 pronotum. 



The name Nerthra was proposed by Say one year 

 earlier than the better known Mononyx of Laporte 

 (Todd, 1952, personal communication). The hemelytra 

 are sometimes undifferentiated into corium and mem- 

 brane in this group and rarely are fused along the 

 mid-line. Two species are known from California, 

 both possessing very distinctive male genital claspers. 

 The commonest species in southern California, Nerthra. 

 martini Todd, was known in all previous literature 

 as Mononyx fuscipes Guer. Todd (1954) has shown 

 that the latter is a more southern species which 

 does not occur in the United States. 



Key to the Genera of Gelastocoridae 



1. Fore tarsi 1-segmented with 2 claws in nymphs and 

 adults; fore femora only moderately enlarged at base, 

 twice as long as wide across base, not subtriangular, 

 the inner side broad, with 2 rows of widely separated 



C D 



Fig. 7:22. a, Nerthra martini Todd, dorsal view of male genital 



clasper; b, N. usingeri Todd, same; c, Ge/astocori's oculatus 



(Fabr.), outline of pronotum; d, G. rotundatus Champion, same. 



short spines in apposition to tibiae; rostrum arising 

 from rounded anterior margin of head, directed backward 



(fig. 7:21a) Gelastocoris Kirkaldy 1897 



Fore legs without a tarsal segment, the single claw 

 (adults) or 2 claws (nymphs) inserted at apex of tibia; 

 fore femora very wide at base, about as wide as long, 

 subtriangular, the inner side extending platelike to 

 form a tuberculate edge in apposition to the tibia; 

 rostrum arising beneath notched anteroventral margin of 

 head, directed backward and then downward (fig. 7:216) 

 Nerthra Say 1832 



Key to the Species of Gelastocoris 



Lateral margins of pronotum strongly sinuate, deeply 

 indented and strongly flaring platelike behind (figs. 

 7:21a; 7:22c); generally distributed 



oculatus Fabric ius 1798 



Lateral margins of pronotum feebly sinuate, only 

 slightly concave anteriorly and bent downward rather 

 than flaring behind (fig. 7:22a"); near Parker Dam, San 

 Bernardino County, California 



rotundatus Champion 1901 



Key to the Species of Nerthra 



1. Length less than 7 mm.; male genital clasper broad, 

 spatulate, at apex with inner side angulate (fig. 7:226); 

 female with last ventral abdominal segment broadly, 

 roundly emarginate on posterior margin; near Parker 



Dam, San Bernardino County usingeri Todd 1954 



— Length more than 7 mm.; male genital clasper abruptly 

 thickened at middle, roundly tapering to subacute 

 tubercle at apex, with a membranous fingerlike pro- 

 jection on inner surface at middle (fig. 7:22a); female 

 with posterior margin of last ventral abdominal segment 



more or less angulately emarginate (fig. 7:216) 



martini Todd 1954 



REFERENCES 



ADAMS, P. A., and C. D. MacNEILL 



1951. Gelastocoris rotundatus Champion in California. 

 Pan-Pac. Ent., 27:71. 

 HUNGERFORD, H. B. 



1922. The life history of the Toad Bug. Gelastocoris 

 oculatus Fabr. Kansas Univ. Sci. Bull., 14:145-167, 

 2 pis. 

 KEVAN, D. K. McE. 



1942. Some observations on Mononyx nepaeformis (Fabr., 

 1775), a toad bug. Proc. Roy. Ent. Soc. Lond. (A), 

 17:109-110. 

 MARTIN, C. H. 



1928. An exploratory survey of characters of specific 

 value in the genus Gelastocoris Kirkaldy, and some 

 new species. Kansas Univ. Sci. Bull., 18:351-369, 

 2 pis. 

 MELIN, D. 



1928. Hemiptera from South and Central America. I. Zool. 

 Bidrag fran Uppsala, 12:151-198. 

 TODD, E. L. 



1954. New species of Nerthra from California. Pan-Pac. 

 Ent., 30:113-117. 



1955. A taxonomic revision of the family Gelastocoridae. 

 Kansas Univ. Sci. Bull. (In press). 



Family OCHTERIDAE 



Ochterids are small, shore-dwelling bugs related to 

 the toad bugs. They are oval in form and dark in 

 color, with yellowish spots. The vertex has two well- 



