FALSE-SCORPIONS 105 



and the silk is rapidly brushed onto the interior of the nest, first in 

 one place, then in another. The animal continues at work gradually 

 imprisoning itself, for days or even weeks until a dense tissue is 

 produced over every part of the inside of its abode (Kew, 1914). 



Food and feeding habits 



Pseudoscorpions are exclusively carnivorous and feed on living 

 or recently killed prey such as CoUembola, Psocids, Thysanura, 

 Diptera, other small insects, Symphyla and Arachnids. Unlike 

 spiders, they are not usually cannibalistic if food is available but an 

 injured or ailing individual has a poor chance of survival. It is 

 doubtful if the prey is actively sought after, but rather that false- 

 scorpions lie in wait, with their claws open, until some suitable 

 animal accidentally brushes against their sensory hairs, when it 

 is seized with extreme rapidity. It is said that some species of 

 Chthonius can actually leap upon their prey. The role of the poison 

 glands in the palps is not entirely clear. Sometimes the prey is 

 paralysed immediately but not infrequently it is conveyed to the 

 chelicerae whilst still struggling. Occasionally one false-scorpion 

 has been observed to rob another of its food after a short struggle 

 (Vachonz/z Grasse, 1949).* 



The protonymph is the most active instar and is quite bold and 

 fearless in its behaviour: it will even take food directly from a probe. 

 The later stages do not feed so readily and adults may eat only 

 once or twice a month. Levi (1948) found that in Chelifer can- 

 croides, adults fed once a week in captivity seemed to be in better 

 condition than those caught in the woods. During feeding the 

 pedipalps may be vibrated, possibly by the action of the pharyngeal 

 pump (Chamberlin, 1931). 



The Argentine false-scorpion Sphenochernes schulzi recently des- 

 cribed by Turk (1953) is very common in the nests of a leaf-cutting 

 ant, Acromyrmex lundi. These pseudoscorpions live buried in the 

 material of the nest and seemingly do not normally emerge except 

 for their prey. They hold their pedipalps open almost continuously, 

 catching at the legs of the ants as they run past, and holding fast 

 until the ant dies from the effect of their poison. The attackers, 

 and there are usually more than one, then probe their victim with 

 their chelicerae, and proceed to suck the body fluids. It is a curious 



