RHYNCHOTA. 
199 
provided with one pair of wings; the hind-wings being rudimentary or altogether 
absent; they have rather long antennae, distinct eyes, and, in some cases, are 
furnished with two long bristle-like 
© 
tails. These winged males are very 
rarely seen, which is accounted for by 
the fact that their mouth-parts are 
atrophied, so that they are incapable of 
taking nourishment, and live only a 
short time. The females are always 
wingless, and usually remain fixed to 
one spot, with their beak buried in the 
tissues of the plant, and their back 
often spread out in the form of a shield 
covering the head and body. The beak 
is generally three-jointed, the antennae 
are short, and in the tarsi, which appear 
at first sight to consist of but one joint, 
two or three joints may on close examination be distinguished, the last ending, as 
a rule, in a single claw. In many species the female dies shortly after laying eggs 
beneath her when her body dries up and remains as a protective cover for them. 
When the larvae are hatched they soon leave this shelter, and rove about the food 
plant in search of a suitable place in which to insert their beaks and begin the 
operation of pumping up the sap. They cast their skin several times in the course 
of their growth; and those which become adult females undergo no great change 
in appearance, beyond an increase in their size, a gradual lengthening of the 
antennae, and a partial or almost complete obliter¬ 
ation of the segmentation of their bodies. With 
the male larvae the case is different; these, unlike 
all others belonging to the order, undergoing a true 
metamorphosis before reaching the perfect state. 
Each prepares for itself a sort of cocoon, and 
it becomes transformed into a quiescent pupa, 
from which, after a certain lapse of time, the 
wi iu r ed insect emerges. In Orthezicc and other 
genera the female, instead of keeping to one spot 
on the food-plant, moves about and taps it at 
different points in order to extract the sap. 
When the eggs are laid, she envelops them in 
a kind of white cottony secretion and leaves 
them. Some species penetrate beneath the 
epidermis of their food-plant, and often cause 
the formation of galls, which, growing up around 
them, sometimes take the most extraordinary 
shapes. Scale-insects are probably more numerous within the tropics than in more 
temperate regions, although comparatively few of these tropical species have been 
described. These insects are found on the bark and leaves, and sometimes 
female of Orthezia urticce (nat. size). 
spruce-gall aphid (Chermes ctbietis). 
a, Larva ; b, An older larva with its moulded skin still 
attached to it; c, Winged insect; d, The gall. (All 
enlarged.) 
