OF THE GAMASIDJ^. 99 



to form a portion of what would be the head, if the mite pos- 

 sessed such an article. They are, however, true feelers, and are 

 never used as legs, the last joint ending in a long hair instead of 

 claws, like the true legs. 



In the genus Gamasus, however, these labial palpi, or first 

 pair of legs (Fig. 3), end in claws and sucker like the rest — though 

 they are used solely as feelers — and never for locomotion. When 

 the creature is stationary, they are generally somewhat raised and 

 bent backwards ; but as soon as it moves, they commence waving 

 backwards and forwards alternately. This species {Gainasus 

 CokoptratoruDi) run very swiftly, and although blind are remark- 

 ably clever at escaping when the glass cover of their cell is raised. 

 The suckers at the end of their feet enable them to run quite 

 easily on glass in any position, and it is evidently by this means 

 that they can stick to the beetle even when it buries itself under 

 ground. They seem sociably inclined, and I often see several 

 collected in one corner of a cell, occasionally tapping one another 

 with their long palpi. In Uropoda the mandibles and lesser palpi 

 are retractile, and together with the maxillae are generally hidden ; 

 but in Gamasus they are always protruded, and their maxillary 

 palpi are constantly employed in brushing the mandibles. I have 

 not yet seen this species in the act of feeding, but have several 

 times watched the smaller kind with the undivided dorsal shield 

 while so employed. 



I will now go back to this Gamasus (Fig. i), and it will sim- 

 plify matters if I continue to call it by the old Linnean name of 

 Coleoptratorum. It is, I believe, the nymphal stage of Gamasus 

 horticola of Megnin, the G. Fucorum of Canestrini. I have had 

 these under constant observation since the i6th of last November, 

 and have endeavoured to find out, if possible, what their natural 

 food is. Megnin says that it is from the liquid products of the 

 decomposition of dead vegetable matter or the excrements of 

 quadrupeds ; and Kramer remarks that damp and decaying vege- 

 tation are necessary to their existence ; and Duges states that 

 almost all Gamasids dry up and die in a few hours after being 

 separated from the insect or stone on which they are found, unless 

 they are kept in a damp vase ; and Andrew Murray, in his work 

 on the Aptera (South Kensington Museum Science Handbook), 



