Comstock and C. Kochi believe that the labrum belongs to it,, The appendages of the posterior three or trophal segments become the parts of the mouth.
In connexion with the operation of the Comstock mines was built (in 1869-1879) the Sutro Tunnel, named in honour of its engineer, Adolph Sutro (1830-1898), piercing the mountain horizontally far below the mouth of the mines, and at a distance of nearly 4 m.
Deep mines, however, are generally dry, so that in most cases it will be possible to realize the more favourable conditions of the Comstock mines.
This was a stock speculation based on the remarkable output ($ 3 00,000,000 in 20 years) of the silver " bonanzas " of the Comstock lode at Virginia City, Nevada, which were opened and financed by San Francisco capitalists.
In April 1872 came the revulsion; there was a shrinkage of $60,000,000 in ten days; then in 1873 a tremendous advance, and in 1875 a final and disastrous collapse; in ten years thereafter the stock of the Comstock lode shrank from $3,000,000 to $2,000,000.