182 NATURAL HISTORY OF OUR SHORES 



pteron named (in science) Acanthia lectularia. It lives 

 under stones, and in the roofs of little caverns, among the 

 sponges and ascidians that crowd those places. It occurs 

 from near high-water level to the lowest zone in tide range. 

 It runs swiftly, and is not easy to capture. 



It is a mystery how these marine insects live, for they 

 cannot rise to sea surface, and have no means of securing 

 a stock of air, as do water spiders ; and Mpophilus, at least, 

 lives in places that do not uncover more than once or 

 twice in the year. 



This insect is fairly common in Jersey, less common 

 in .the other Channel Islands. It is found in Cornwall, 

 and most likely on all our shores, although it has not been 

 widely recorded. 



The visitor to the low-tide zones must frequently have 

 noticed swarms of small flies hovering over the water 

 surface, and in little caves and rock clefts, and wondered 

 what became of them when the tide returned. 



These are dipterous flies, named Clunio marinus. Their 

 larval stages are passed under water, and their lease of 

 life, when once the perfect stage is reached, is very brief 

 most likely only about six hours. There is a second 

 species recorded (Clunio bicolor), but it only differs from the 

 former in microscopical detail. 



The Marine Arachnida are represented by several forms. 



Firstly the Pseudo scorpions. Of these one species 

 (Obisium marinum) has long been known. A second species 

 was discovered by myself in 1889, or I had better say I 

 was in the joint discovery, for, by a strange coincidence, 

 when I announced the discovery in Nature it was also 

 announced from France (Boulogne), and this on the same 

 day, September 29th. 



The mites (Acarina) are represented by several species, 

 ranging from high-tide level to many fathoms deep, but 

 I do not know if they have been listed. 



