158 THE NORTHERN MICROSCOPIST. 
kept two Dytiscus beetles for some time, informs me that the 
female easily killed the male while he was watching them. This 
sort of occurrence is not uncommon amongst the denizens of our 
ponds, for often if a worm be dropped between two newts, both 
make a grab at it, and owing to its wriggling miss it, and catching 
each other by the foot they fight like bull dogs. 
We may now take a glance at the internal economy of this beetle, 
contenting ourselves, however, with a view of his digestive system, 
which will furnish you with plenty of work before you have 
made out all the structures. 
At A (fig. 27) may be seen the cesophagus ; at the end of which 
iM 
Fig. 27. 
follows the gizzard B. The food, when triturated here, is passed 
into the stomach D, from whence it travels through the small 
intestine E, into the large ‘oval-shaped sac on the left of the figure, 
which is the large intestine. 
