Fig. 7:39. o, Mesovelia omoena Uhler, male genital segments, 

 ventral view, b, M. mulsanli White, same; c, M. amoena Uhler, 

 hemelytra with only two closed cells, the membranous area 

 broken off. 



223 



Usinger: Hemiptera 



REFERENCES 



HOFFMANN, C. II. 



1032. The biology of three North American speciea of 

 Mesovelia. Canad. Frit., 64:88-13:5. 1 pi. 

 HUNGERFORD, H. B. 



1917. The life history of Mesovelia mulsanli White 

 r yrche, 24:73-81. 

 JACZEWSKI, T. 



1930. Notes on the American species of the genus 

 Mesovelia Muls. Ann. Musei Zool. Polonici, 9:3-12. 

 3 pis. 

 USINGER, R. L. 



1942. Notes on the variation and distribution of Mesovelia 

 mulsanti White. Bull. Brooklyn Ent. Soc, 37:177-178. 



at least from southern Canada (British Columbia) 

 throughout most, if not all, of the United States and 

 Mexico. Scarcity of records from the Pacific Coast is 

 owing in part to lack of collecting and in part to a 

 peculiarly discontinuous distribution. Usinger (1942) 

 first recorded the species from California, taking it 

 in a bog lake in the central part of the Sierra Nevada 

 (Swamp Lake, Yosemite National Park). Although 

 common in this one lake, it has not been found in 

 other places in the Sierra in ten years of collecting. 

 Elsewhere in California mulsanti has been found 

 commonly in scattered localities from Tule Lake in 

 the north to the Colorado River in the south. 



The taxonomy of M, amoena is even less clear, 

 but if, as suggested by Jaczewski, M. douglasensis 

 Hungerford is a synonym of amoena, then the published 

 distribution of the species is: Michigan, Florida, 

 Louisiana, Mississippi, and Texas; Puerto Rico and 

 Grenada in the West Indies; and Brazil and Panama. 

 I can add Jamaica and three localities in California — 

 Death Valley, the Colorado River near Bard, and 

 Borego Palm Canyon. 



Taxonomy. — The family Mesoveliidae is small, less 

 than two dozen species having been described in four 

 genera for the world. Three of the genera are mono- 

 typic. The species of Mesovelia are easily distin- 

 guished by characters of the penultimate abdominal 

 segment (first genital segment) in the male. The 

 presence or absence and number and arrangement of 

 tufts of hair on the ventral surface of this segment 

 are diagnostic for most species. In addition to this, 

 the usual proportions of appendages are used and, in 

 amoena, the venation of the hemelytra. 



Key to the California Species of Mesovelia 



1. Length more than 3 mm. Front and middle femora armed 

 beneath with a row of black spines. Males with 2 black 

 tufts of minute spines on the ventral side of the 8th 

 abdominal segment. Macropterous specimens with 3 

 closed cells in the hemelytra. Rostrum extending only 

 to hind margins of middle coxae (figs. 7:37, 7:38, 7:396) 



mulsanti White 1879 



— Length about 2 mm. Front and middle femora without a 

 row of black spines beneath. Males without black tufts 

 on the ventral side of 8th abdominal segment. Macro- 

 pterous specimens lacking the small closed cell at 

 apex of corium. Rostrum extending to apices of hind 

 coxae (fig. 7:39a, c) amoena Uhler 1894 



Family SALDIDAE 



Shore Bugs 



Saldids are intermediate in structure and in habits 

 between the terrestrial bugs and the true water bugs. 

 They have exposed antennae like land bugs but are 

 able to survive in or on the water when they acciden- 

 tally land on the surface after a jump or when they 

 are submerged on beaches at high tide. 



Saldids have four-segmented antennae, a long, slen- 

 der, three-segmented beak, and large eyes with the 

 inner margins notched behind like many water bugs. 

 There are two well-developed ocelli and pairs of 

 erect trichobothria on the vertex. The legs are rela- 

 tively slender but permit rapid movements including 

 leaps which, when combined with short flights, provide 

 a ready means of escape. The nymphs are oval in 

 outline like the adults but have only two-segmented 

 tarsi instead of three (the first being very small in 

 both stages). There is only a single dorsal abdominal 

 scent gland opening in the nymphs. The rostrum is 

 long, slender, three-segmented, and tapering. The 

 body is clothed with one or more types of pubescence 

 which serves to protect them from wetting. Drake and 

 Hottes (1951) have noted peglike or spinelike "stridu- 

 latory" structures anterolateral^ on the second 

 visible connexival segments of males. 



Life history.— Hungerford (1920) and Wiley (1922) 

 have given accounts of the biology of some of our 

 species. In general, it appears that they overwinter 

 as adults, lay eggs in the spring and early summer, 

 and develop through five instars in about a month. 

 The incubation period of the egg for Saldula major 

 (Prov.) in Kansas was found by Wiley to be 12 days, 

 and the length of nymphal instars was: first, 4 days; 

 second, 6 days; third, 3 days; fourth, 2 or 3 days; 

 fifth, 4 days. Saldula pallipes Fabr. followed essen- 

 tially the same pattern. The eggs are elongate, larger 

 and more broadly rounded at one end, tapering and 

 smaller at the other end, with the dorsal part arched. 

 They are laid at the bases of clumps or between the 

 leaflets of moss or other marginal vegetation. 



Habitat and distribution. — Saldids are typical in- 

 habitants of the beaches and shore lines of lakes, 

 streams, and ocean. They also inhabit springs, bogs, 

 and salt marshes. In a sense, they are not aquatic 



