38 NOTES ON 
The rostrum, or beak, is hard and pointed. 
In some of the larger species it has sufficient 
strength to effect a severe puncture and wound. 
As this part is foreshortened in the drawing, I 
have here given a sketch of the head and ros- 
trum of the Notonecta glauca magnified. Its 
covering is of a strong corneous texture; it has 
a channel down the middle, and is terminated 
by a strong hard point; the eyes are prominent 
and compound. 
The wings of the perfect insect are delicate 
and transparent; they are folded under the 
wing cases, which overlap each other along the 
anterior margin; they are variegated in some 
species, and striated in others. The folds of 
the wings are shewn at a in the following 
figures; the larger one is the wing of the glauca, 
