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[Reprinted from ‘THe Zoouoetst’ for June, 1907.) 
AOWATIC COCKROACHES. 
By R. SHeurorp, M.A., F.L.S. 
In 1897 the writer was collecting insects on a mountain close 
to Kuching, the capital town of the State of Sarawak, in Borneo, 
and, whilst examining a small pool at the base of a waterfall for 
water-beetles, discovered several Cockroaches lurking in the sod- 
den leaves scattered about the edge of the pool. The insects, 
when disturbed, took to the water, and dived to the bottom, 
where they hid under sticks and stones. The habit was suffici- 
ently remarkable and unexpected to deserve further investigation, 
and several specimens were captured alive, and placed in a glass 
tank with some water and an abundance of vegetable débris. All 
the specimens were immature, and of varying size, ranging from 
10 millim. to 25 millim. in length. It was observed that they 
could not endure total immersion in water for any length of 
time; if a specimen was confined in a tube full of water, and 
denied all access to air, it would struggle violently for a few 
minutes in its efforts to escape, and then sink to the bottom of 
the tube, and there expire. This is what one might expect from 
the results of certain experiments conducted by Prof. Plateau, of 
Ghent, on the relative staying powers of land- and water-insects 
when totally submerged in water. The distinguished Belgian 
entomologist found that, whilst terrestrial insects will support 
an immersion for a period ranging from 973 hours to 22} hours, 
aquatic beetles succumb in periods ranging from 653 hours to 
3 hours. The aquatic Cockroach drowns even more rapidly than 
aquatic beetles, and it was found that a terrestrial Cockroach, 
though enduring total immersion for a few hours, is unable to 
remain alive without air for even the minimum time recorded for 
terrestrial beetles. 
The aquatic Cockroaches that were kept under observation 
were very inactive, resting for hours at a time on the dead leaves 
with which they were provided ; generally the front part of the 
