1899] COLOMBIAN ORE 295 
the specimens begins. Preceding such descriptions there is in each case a 
preliminary historical account of the mining done in the district from which the 
specimens were collected. The sulphide ores are chiefly those of silver, zine, 
mercury, lead, and iron, and occasionally of antimony, etc., while large amounts 
of native gold, silver, and sometimes copper are present in many of the districts. 
Among the sulphides pyrites is very common, and this is sometimes auriferous, 
Occasionally copper pyrites, mispickel, stibnite, cinnabar, tetrahedrite, pyr- 
rhotite, enargite, etc., are present. The gold is frequently associated with 
tellurides. Many interesting examples of paragenesis are given, but to enter 
into details would be wearisome to the general reader, although they might be 
perused with avidity by those interested in the mines of this republic, while 
the mineralogist could not fail to find some useful information in them. One 
of the most important points with which the author has dealt is the true 
signification of the names of rocks hitherto employed by former writers when 
describing these mines. For instance, for the old terms syenite and granite, the 
author points out that one may generally read andesite or trachyte; “ horn- 
blendic material” usually is found to be a rock allied to chlorite schist, and 
several other examples of the former misapplication of names, owing to lack of 
the present means for determining the mineral constitution of rocks, will be 
found in these pages. The author has done useful work in solving some of 
these enigmas. 
In the “‘ General Conclusions,” p. 172, he remarks that ‘the gold and silver 
ores of Colombia occur either in the acid lavas, which have been erupted at 
intervals from the close of the Tertiary to the present time, or in Archaean 
schists in the immediate vicinity of the lavas. In the schists they are usually 
poor in depth. Owing to the action of the heavy tropical rains, the weathered 
zone of the deposits has often been greatly enriched, and it was such enriched 
deposits that gave the immense yields of the early days of Colombian mining.” 
Three pages, giving the literature relating to Colombian mines, are followed 
by a map, on which considerable labour has evidently been expended in order 
to render the topographical details trustworthy. F. RUTLEY. 
COCCIDOLOGY. 
The Coccidae of Ceylon. By E. Ernest GREEN. Part I. 1896; pp. 
i.-xi. + 103, with pls. 1-30. Part II. 1899; pp. xiii.-xli., 105-169, and 
pls. 31-60. London: Dulau and Co. 
The Coccidae constitute an aberrant group of the Hemiptera, contradicting 
all ordinary definitions of the order and class to which they belong. Hemi- 
pterous hexapods, yet in the female sex wingless, and in many genera legless 
as well. The very methods by which they must be studied are peculiar, and 
as such distasteful to the ordinary entomologist. 
So it has happened that these creatures, though numerous and peculiar, 
have been greatly neglected. But in recent years, as though outraged by such 
persistent scorn, they have risen in their might and played havoc with our 
fruit trees and other crops, not to mention ornamental plants ; wherefore we 
have been obliged to recognise their existence. 
Studies usually begun with economic ends in view have led us far afield. 
It becomes plainer every day that the Coccidae are not only extremely numerous 
in species, but offer an extraordinary series of peculiar forms, whose organisation, 
as related to their environment and habits, is of the greatest interest from a purely 
biological standpoint. The opportunity to advance both economic entomology 
and pure science is too good to be neglected once perceived ; and so we find a 
new body of students arising, calling themselves coccidologists, and dignifying 
their study by the name of coccidology. 
Of these latter-day students assuredly E. Ernest Green is second to none. 
