THE FAUNA OF A DESERT TRACT IN SOUTHERN INDIA. 217 



little in progression and generally brandished in the air like antennae. (The two distal 

 joints of these legs are somewhat enlarged and are quite devoid of hair.) The palpi 

 were also employed in removing the sand-grains. As soon as a slight cavity had been 

 formed in this way, the cephalothorax and the anterior part of the abdomen were 

 inserted into it. The liquid, or semi-liquid, contents of the abdomen were then squeezed 

 away, by contraction of the body all towards the posterior extremity, which became 

 rounded and globular. A little more of the abdomen was then inserted, and its contents 

 were then moved forward ; so that the animal progressed downwards by alternately 

 contracting and dilating itself in a slow and orderly fashion. 



The material which rendered this action possible is a yellowish oil, which becomes 

 darker and more solid on exposure to the air. The whole body cavity was closely 

 packed with this substance, but not so closely as to render the abdomen turgid. This is 

 evidently the oil used as a drug in Northern India and lately analysed by Mr. Hill, the 

 red colour he ascribes to it being due to the pigment of the integument, which must have 

 been extracted with it and not due to any constituent of itself. The pigment fades 

 slowly in spirit ; probably owing to a misunderstanding as to its nature and uses, 

 Europeans, both in Northern and in Southern India, frequently call the Mite the 

 "Cochineal Insect." Doubtless the oil has a double function, (i) as a reserve food- 

 supply which may be gradually drawn upon during aestivation or during brief periods of 

 activity; and (2) as a hydraulic agency in burrowing. 



I notice that Ants, which in Calcutta even kill living cage-birds, and remove, as 

 a rule, any particle of fresh animal or vegetable matter to which they can gain access, 

 take no notice of either dead or living specimens of the Mite. The same is true ol 

 Cockroaches and of Spiders belonging to the families Attidae and Thomisidae, to which I 

 have offered the Mites; while a hungry Harrewa (Chloropsis jerdoni), which immediately 

 afterwards eat a grasshopper, did not make the slightest attempt to peck at a living 

 Trombidium placed before it in its cage, but, on the contrary, seemed alarmed and 

 avoided the part of the floor of the cage on which the Mite was crawling. 



REMARKS ON DISTRIBUTION. 



The interest of the collection is, from a geographical point of view, mainly nega- 

 tive. The great majority of the species represented have a wide distribution and are 

 able to exist in environments of many different characters. Such a form, for example, 

 as Blatta supellectilium is spread through the tropics of both Hemispheres and occurs both 

 in arid and in extremely damp localities. Even more striking is the case of another 

 widely distributed Cockroach, Stylopyga rhombi folia ; for this species cannot fly from one 

 place to another, and yet it is by no means confined to the close proximity of man. It is 

 all the more curious to find that its ally, S. ornata, is apparently a rare and local form, although 

 there is nothing in the specific characters of either species which would explain this dif- 

 ference in distribution. Both the Cockroaches last named are, to some extent, modified 

 species, the wings having become degenerate; while Pseudoglomeris flaviconiis has under- 

 gone very much greater modifications in adaptation to its mode ot life, the retiring 



