G. S. Graham-Smith 
521 
without tactile hair, tactile hah- of tarsus near middle. with galea poorly developed, 
hand a little narrow, coxae iv differing little from ?. L. 1-7. 
Among vegetable refuse, in rubbish heaps, etc.; sometimes abundant; probably 
widely distributed: Essex, Kent, Surrey, Sussex; also about decaying trees; New 
Forest; in nests of Formica rufa ; in nests of Bombus muscorum." 
Several views have been put forward to account for the habit of 
seizing flies. 
(a) Some have regarded the pseudo-scorpions as parasites which 
obtain nourishment from the bodies of the living flies. In the majority 
of carefully observed cases no injury to the leg of the fly was noticed 
and there is little evidence that the creature makes its way up the leg 
to the body in order to reach the less chitinous parts of the fly, though 
occasionally it is found attached to the body and not to the leg. Donovan 
(1797) noticed one “fastened on to the body of Musca vomitoria, the 
common flesh-fly, from which it could not be extracted without killing 
and tearing the fly to pieces,” and Kirbv and Spence (1826) state that 
“they adhere to it (the common blue-bottle fly) very pertinaciously 
under the wings.” 
(b) According to another view the pseudo-scorpion is predaceous, 
remaining attached to the fly until the insect dies and then sucking its 
juices. Undoubtedly the pseudo-scorpions cling to flies with great 
tenacity and the latter, although they constantly make efforts, seldom 
seem to succeed in getting rid of them. Even when the fly is captured 
and handled the pseudo-scorpion seldom relaxes its hold. Moore (1835), 
however, once saw a pseudo-scorpion voluntarily drop from a fly. 
Hess observed a chelifer hanging on to a fly’s leg without altering its 
position for 56 hours, and Stainton (1864) stated that in his experience 
the chelifers did not quit the flies until the latter died. Lukis (1831) 
on one occasion saw a chelifer dragging about the dead body of a 
Stomoxys. Backhausen made some very interesting experiments which 
seem to support this view. He placed a fly with a pseudo-scorpion 
hanging to one leg under a glass. Next morning he found the fly dead 
and the pseudo-scorpion fat and bloated under some scraps of paper. 
“He next placed ten pseudo-scorpions on a tray with earth and 
leaves, put them under the glass, left them for a few days without 
food, and then imprisoned a few small flies. As soon as the pseudo¬ 
scorpions perceived the presence of the insects they came out of hiding 
and began to snatch at them, attaching themselves to their legs, always 
with one pincer, but using the other in their endeavours to obtain an 
assured holding. Once fixed they continued to hold to the leg.” The 
