209 

 Usinger: Hemiptera 



B 



Fig. 7:21. a, Gelastocoris oculatus (Fabr.) Mokelumne Hill, Calaveras County, California, 

 May 27, 1931, (R. L. Usinger); b, Nerthra martini Todd, Frenchman Flats, Tehachapi Mountains, 

 California, April 8, 1951, (R. L. Usinger.) 



i 

 4 



TORRE-BUENO, J. R. de la 



it 1906. Life history of Ranatra quadridentata. Canad. Ent., 

 38:242-252. 



Family GELASTOCORIDAE 



Toad Bugs 



Toad bugs are squat, compact, mud and sand inhab- 

 itants with prominent eyes, raptorial front legs, ocelli 

 more or less distinct, and hemelytra usually separate 

 and fully developed but sometimes with the membrane 

 'reduced and rarely with the hemelytra fused. The 

 nymphs lack dorsal abdominal scent gland openings. 

 Life history. — From the meager records at hand 

 Gelastocoris overwinters as an adult. Eggs are laid 

 I in the sand. They are broadly oval with roughly granu- 

 lar surface, 1.25 mm. long and .91 mm. in diameter. 



Nerthra eggs were laid in small holes in the mud 

 beneath stones several feet from the water's edge. 

 Most remarkable was the fact that in both instances 

 when eggs were found, the female Nerthra was in a 

 position on top of the egg cluster in the hole. Since 

 the eggs were in an advanced stage of development 

 as indicated by conspicuous eyespots, it is suggested 

 that females may remain with (guard?) the eggs 

 throughout the incubation period. 



Feeding habits. — Hungerford (1922) fed his Gelasto- 

 coris oculatus on a variety of insects taken by sweep- 

 ing grass. In the natural habitat they no doubt pounce 

 upon any helpless creatures of small size. Kevan 

 (1942) reports that A', nepaeformis (Fabr.) took ter- 

 mites and a soil-dwelling earwig (Euborella sp.) in 

 Trinidad. 



Habitat. — As mentioned above, Gelastocoris is found 

 on sandy and muddy shores of ponds and streams. The 

 mottled color pattern renders them inconspicuous 

 The incubation period in Kansas (Hungerford, 1922) against their normal background. Gelastocoris oculatus 

 was found to be 12 days. The average length of each is an extremely variable species and superficial 

 of the five nymphal instars was: 15 days, 16, 15, l&A, observations would suggest that this variation is 

 22. No member of the genus Nerthra has been reared correlated with the color of the substrate. Hungerford 

 through a complete life history, but Kevan (1942) tried to test this "by placing them in pans containing 



found that the last nymphal instar of N. nepaeformis 

 (Fabr.) lasts for at least two weeks. Egg laying was 



' observed in N. martini Todd at Frenchman Flats, 

 Tehachapi Mountains, California, in June. The eggs 



i are similar in form to Gelastocoris but are longer 



(1.35 mm.) and smaller in diameter (.85 mm.). The ently by me in California. 



sand on one side and sandy loam on the other" but 

 reports that his results were inconclusive. 



Nerthra occurs in muddy situations and often at 

 considerable distance from the water. This was noted 

 by Kevan (1942) in Trinidad and confirmed independ- 



