ADAPTATIONS TO HAUNTS AND SEASONS 293 



endure submersion, creeping about under the salt water 

 at high tide. Allied to the Saldidae is the remarkable 

 Aepophilus bonnairei, regarded as the type of a distinct 

 family, the only member of the order that lives between 

 tide-marks on our coasts, where it is found in the same 

 situations as the beetles Aeptis marinus and A. robiniiy already 

 mentioned in this chapter ; hence the name conferred on 

 it by its discoverer V. Signoret (1880). It is an elongate, 

 flattened hairy bug (Fig. 57), resembling the bed-bug in 

 its vertical compression as well as in the absence of hind- 

 wings and the vestigial, pad-like condition of the strong 

 forewings. R. Koehler (1885) found these insects on the 

 coast of Sark beneath large stones in a cave, entrance to 

 which is only possible to human beings four times a year-, 

 J. H. Keys, whose observations on the family life of these 

 bugs have been previously mentioned (p. 212), found the 

 insects to occur in greatest numbers beneath large boulders 

 in a channel far out beyond a reef of rocks, a locality covered 

 by the sea for twenty hours of the twenty-four. They 

 cannot apparently survive prolonged immersion in sea- 

 water, nor can they walk on the surface ; " they hide in 

 companies in little holes in the stone, packed together as 

 closely as possible, or rest on the algaic growth thereon." 

 In such shelters though submerged they are encased in air- 

 sacs and not really immersed. Aepophilus is apparently a 

 scarce insect with a range restricted to the coasts of south- 

 western Europe, the Channel Islands, south-western England, 

 and southern Ireland. 



The most highly specialised and strongly adapted among 

 marine Hemiptera belong to the family (Gerridae) of the 

 pond-skaters and their allies. The common Velta currens 

 of our streams (p. 282) has in the tropics relations known as 

 Rhagovelia, in which the legs of the middle pair are excep- 

 tionally long and provided with a system of branching 

 feathery hairs set in the deep cleft of the terminal segment 

 of the foot. These can be retracted and hidden within the 

 cleft of the foot or spread out like the spokes of a wheel to 

 provide a disc-like area of support on the surface-film. 



