April, 1913. 



KNOWLEDGE. 



127 



others are hewn out of the solid rock. There are 

 present a few examples of ancient masonry in which 

 the stones are cemented together with no little 

 skill, and there are also wells of considerable depth, 

 formed of stones closely cemented in a similar 

 manner. 



A partly obliterated raised roadway or terrace 

 can be traced extending for a considerable distance 

 in the direction of the Red Sea. 



A peculiar feature of the district is the presence 

 of a good many crudely formed obelisks, each 

 consisting of a huge roughly hewn mass of stone, 

 with somewhat smaller ones lying at the base. 

 It is probable that these once had some significance, 

 but with what intention they were erected none can 

 decide, although some think they answered the 

 purposes of signposts. 



On the walls of some of the buildings, especially 

 on those of the temples, inscriptions are to be seen. 

 Those which have been deciphered, although of 

 great interest, do not help to solve the riddle of the 

 mines. 



The interiors of the barrack-like buildings have 

 walled-up recesses surmounted by slabs of stone 

 slanting downwards from the apex. Immediately 



below the apex is invariably to be found a stone 

 image of a god, placed there for some reason 

 connected with the religion of the departed race. 



It is difficult to imagine a more w r ild region than 

 the country surrounding these emerald mines, and 

 yet there is a majesty of beauty in the hideous bare 

 mountains, through which meanders a graceful 

 wadv of rock and coarse sand at almost everv 

 turn. (See Figure 124.) 



With the exception of here and there an isolated 

 stunted tree, there is next to no vegetation. A few- 

 wandering Bedouin Arabs, ever in search of the 

 water, which they rarely find, form the only 

 inhabitants of this drear spot, which thousands 

 of years ago must have echoed with the hum of 

 busy slaves toiling to supply their rulers with a 

 useless gewgaw. 



Dr. Max Bauer, in " Precious Stones," states that 

 gold and topaz are found in the range of mountains 

 in which the emeralds occur. 



For information and the photographs the writer 

 is indebted to Mr. Edwin W. Streeter who 

 pioneered an expedition in the mines, and to Mr. 

 Allan Forster and Mr. F. Grote, two members of 

 his party. 



TROMBIDOIDEA. 



By CHARLES I). SOAR, F.L.S., F.R.M.S. 



Naturalists, particularly those naturalists who study the 

 minute forms of animal life with the aid of the microscope, 

 have not paid much attention to the British Acarina. Why 

 the study of mites has been so much neglected in Britain 

 cannot be for want of specimens, for they can be found almost 

 anywhere. One reason may be on account of their minute 

 size, and the trouble that has to be taken to find them. 

 Another reason is, no doubt, the dearth of literature on the 

 subject. As yet we have only two monographs on British 

 mites, although there are a large number of papers distributed 

 about in the different natural history and microscopical 

 journals. There are several acarologists on the Continent 

 who are doing some splendid work with the mites, but they 

 are outside the Britannic area. Nevertheless, their papers 

 are very useful for the description and identification of what 

 mites we find here. The water mites found on the Continent 

 are nearly all found here in the British Isles, so it will no 

 doubt be the same with the land mites. 



Except in the case of some of the families of the Sarcoptoidea 

 and Ixodoidea, there is nothing repulsive about the study of 

 mites, and they all exhibit a great variety of form and colour. 

 Their life-history is only known in a few cases, but we know by 

 experience what a great part they play in nature's economy. 

 The'Aj is plenty of original work waiting to be done, and it 

 would be worth doing. There are about thirty families of the 

 Acarina waiting for their history to be studied and written in 

 the British Isles. Two families have been done, and done 

 well, the Oribatidae and the Tyroglyphidae, by Mr. Michael, 

 F.L.S., both published by the Ray Society. 



Let us just glance at the super-family Trombidoidea. This 

 is divided into six families : — 



First, Trombididae, commonly called harvest mites. The 

 small, red, velvety mites we find on our garden borders belong 

 to this family. All the mites of this family are red, some 



darker than others. The body is covered with feathered 

 hairs, according to the species. A monograph on the Trom- 

 bididae has just been published by A. Berlese. He has 

 divided the family into fifteen genera, and gives a coloured 

 figure of each type species. Dr. George, of Kirton-in-Lindsey, 

 has published some papers in The Naturalist on these mites, 

 but the subject is only begun as yet. 



Second, Caeculidae. This is a small family of rather 

 large mites, found in moss, fallen leaves, and moist places, 

 rectangular in shape, and with very rough legs. They are 

 found in Southern Europe, but I have not yet seen any record 

 for Britain. 



Third, Khyncholophidae. Several species of this family 

 have been recorded by Dr. George in The Naturalist, repre- 

 senting different genera. There was one particularly beautiful 

 mite, with plumes on the fourth pair of legs. It is known as 

 Eatoniana plumifer, and I think was found in Jersey. It 

 is common in Southern Europe and North Africa. I think 

 Dr. George's record is the only one for the British Isles. 



Fourth, Cheyletidae. A small family of little mites. They 

 are distinguished by the enormous palpi attached to a distinct 

 beak. They are animal feeders, some predaceous, some 

 parasitic, divided into about eight genera. Two or three 

 species have been recorded for the Britannic area. 



Fifth, Erythraeidae. Quite a small family, containing only 

 four genera. They are red in colour, quick in their movements, 

 and very erratic in their course. 



Sixth, Tetranychidae. These are well known as the 

 red spiders. Several have been recorded for Britain. They 

 are divided into about eight or nine genera. The genus 

 Bryobia appears to be the most common. 



The super-family Trombidoidea is a large one, and represents 

 with its six families a large number of genera, but it would 

 well repay anyone to take up any single family and work it 

 out. 



