PENTATOMID.E. 
669 
hemelytra ; the scutellum is large, either covering the whole abdomen, 
or occupying a large portion of the base of the abdomen between the 
hemelytra. In the former case the 
hemelytra, protected by the scutellum, 
are not thickened at the base but are 
membranous throughout. The hemelytra 
fit closely to the abdomen, the apical 
membranous half of each overlapping. 
The lower wings are below the hemelytra 
and both pairs function in flight. Wing¬ 
less species with abbreviated or much 
reduced hemelytra occur. There are 
small orifices of the scent-glands on the 
ventral surface of the thorax, whose 
position is useful in the discrimination 
of genera. The abdomen is short and thickset, its margin in some 
cases is visible from above and not covered by the hemelytra. 
The integument of the whole body is so rigid that the relative positions 
of the parts are accurately maintained and are useful in classification, 
a statement that can be made only in the case of this family, 
and the Coleoptera . Males and females are commonly similar in 
external appearance, the former sometimes smaller. 
The life-history is similar throughout the family. Eggs are laid in 
clusters on plants or elsewhere in the open ; these eggs are commonly of 
the shape of an upright cylinder, about one-tenth of an inch high, with a 
flat cover on the top (like a barrel). When they hatch, this cover opens, 
either being attached at one side or coming completely off. The young 
insect is flattened, the body nearly round, and is active. It feeds on the 
juice of plants and passes through a number of moults with the gradual 
development of wings, etc., till it is full grown. The tarsi usually have 
only two joints, the third developing at the last moult: the odoriferous 
glands are in the abdomen and open on the dorsum at the apex of the 
third and fourth abdominal segments. The colouring of these young 
insects is commonly different to that of the adult and often very striking 
The number of moults is usually five ; the nymphal life is commonly 
short, the imaginal being the long and active period to which the 
nymphal is subordinated. The adults are found upon plants, upon 
Fig. 437— SCUTELLEKA NOBILIS. 
EGGS AND NYMPHS. 
(After de Nicevitle). 
