
92 THE INSECT WORLD. 

illustrious Swedish naturalist, De Geer, because our young Teau. | 
have most likely met with this insect, or will do so some day 
when gathering raspberries. | 
The Grey Pentatoma, marked with black, yellow, and red, is to 
be found throughout the whole of Europe in cultivated fields and 
gardens, sometimes also on the trunks of large trees, especially 
elms. This species, in common with the greater part of those which 
compose the group we are describing, emits a smell when 
‘irritated or menaced with some danger. At other times no odour 
subject. 
“Seize the pentatoma with a pair of pincers and plunge it into 
a glass of clear water; examine it through the magnifying-glass, 
and you will see innumerable small globules arising from 
its body, which, on exploding on the surface, at once exhale 
that odour which is so disagreeable. This vapour, which is 
essentially acrid, if it touch the eyes causes a considerable 
amount of irritation. If one of these insects is held between 
the fingers, so as not to stop up the odoriferous orifices, and to 
cause this vapour to touch a part of the skin, a spot, either 
brown or livid, will ensue on that part, which lotions, though 
repeatedly applied, will at first fail to remove, and which produces 
‘1 the cutaneous tissue an alteration similar to that which suc- 
ceeds the application of mineral acids.” 
The disagreeable smell exhaled by different species of Pentatoma 
+s the result of a fluid secreted by a single gland, of pyramidal 
form, and either red or yellow, which occupies the centre of the 
thorax, and which terminates between the hind feet. 
With the Syromastes, which are bugs of this same group, the 
secretion has, on the contrary, an agreeable smell, which reminds 
one of that of apples. Many kinds of Pentatoma are destructive 
to agriculture. Others, however, attack the destructive insects, | 
and ought therefore to be carefully spared. We will mention in : 
this case the Blue Pentatoma, which kills the Altica* of the vine. | 
There may be observed, at the foot and about the lower part of | 
trees, or at the base of walls exposed to the mid-day sun, groups : 
of fifty or sixty small insects pressed close to each other, and often : 
will be noticed. Let us hear what M. Léon Dufour says on this 
* A genus of beetles.—Ep. 

