142 HARVEST-SPIDERS 



adult harvestmen: usually they retreat after one bite and wipe their 

 mouths on a leaf. In no British species is the odour discernible to 

 man: the fluid is colourless and does not appear to have any marked 

 flavour, but various Gonyleptidae in Brazil produce a strong, 

 nauseating odour if handled, and in addition can deliver a sharp 

 pinch by firmly drawing their hind femora together behind them. 

 Odoriferous glands are found in both sexes of all species of harvest- 

 spider and in their nature are very similar to those of millipedes. 

 As already mentioned, there is a single pair of glands which opens 

 at the margin of the cephalothorax above the coxa of the second 

 leg. In the larger South African Laniatores such as Larifugella 

 natalensis, the opening is protected and partly covered by a large 

 flattened tubercle or process of the coxa. In some species the gland- 

 ular secretion can be discharged in the form of a fine jet to a dis- 

 tance of more than an inch from the animal (Lawrence, 1937), but 

 in most it merely flows from the gland opening. The colour of the 

 secretion in the Laniatores is bright yellow or reddish brown: it is 

 highly volatile with an acrid smell and may cause a smarting 

 sensation in the eyes if a drop is brought too close to them. 



Their repugnatorial fluid may be responsible for the fact that if a 

 number of phalangids are confined in a limited space they seem to 

 be anaesthetised or narcotised by each other and remain for a long 

 period in a state of insensibility. When thrown out upon the floor 

 of a cage they promptly recover and run about normally (Savory, 

 1938). The same phenomenon has been observed by Bishop 

 (1949b): the specimens lie in a tangled mass of legs and bodies, 

 apparently without life, but when disturbed by shaking they re- 

 cover and assume their normal activities. 



The parasites of Opiliones include nematode worms and gre- 

 garines, while several species have been found with larval mites 

 such as Erythraeus phalangioides, Belaustium nemorum, Leptus spp. 

 and other Thrombidiidae which are a conspicuous bright red colour, 

 attached to them. Phoretic false-scorpions are occasionally to be 

 seen clinging to their legs. According to Forster (1954) the New 

 Zealand Laniatores are not attacked by spiders but infestation by 

 nematodes and Chalcid wasps has been noted. Specimens are often 

 heavily infested with mites which cling to intersegmental mem- 

 branes of abdomen and appendages. 



