Tae NortHERN MuiIcRoscoPIst. 
No. 7. JULY. 1881. 
DYTISCUS MARGINALIS. THE GREAT WATER 
BEETLE.” 
By W. RipeEouT, F.R.M.S. 
POND is to its inhabitants what the world is to us, and a very 
interesting world it is, not only to its own denizens, who no 
doubt consider it (whatever fault we may have to find with it) 
the finest place under the sun ; and wisely so, for ‘‘ where ignorance 
is bliss ’tis folly to be wise.” But some may say, “ What do you 
find in ponds except mud, dead dogs, and duck-weed?” The an- 
swer is, “ Life !”—life in all its diversity of forms, beautifully and 
wonderfully arranged ; each individual deriving benefit from the 
well-being of the mass, the mass often prospering in inverse ratio 
with the individual. To the microscopist a productive pond is 
simply a world of wonders. Here he finds minute forms of life 
beautiful in the extreme, and admirably adapted for the life they 
lead. If the visitor to the pond side does not happen to be a micros- 
copist, then he will find ample amusement and instruction in 
watching the larger creatures which inhabit its waters, such as 
frogs, newts, beetles, and fish, each presenting peculiarities well 
worthy of his close attention. I have selected for consideration 
a common inhabitant of our ponds and rivers, Dytescus Marginalis 
—sometimes spelt Dyticus—the Great Water Beetle, or Water Devil 
(fig. 23); who, judging from the way in which he comports 
himself when removed, evidently considers it his private property, 
bagging his game as opportunity offers, in fact sporting seven days 
to the week, and resisting any attempt at capture by all the means 
in his power. 
Of Dytiscus marginalis may be said, as was said of a large sample 
of humanity long ages ago, that he is a warrior from his youth up, 
__* A paper read before the Manchester Scientific Students’ Association. The 
illustrations have been prepared by photographing the actual specimens exhibited 
by Mr. Rideout. 
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