42 
HALF HOURS WITH INSECTS. [Packard. 
attached. In the Pine-leaf Scale insect (Fig. 32 ; a, the leaves 
with the scales of natural size ; 6, male scale ; c, female. Fig. 
29, the male greatly enlarged, after Riley) the scale marked 
d is much wider than in the one marked c, which lives on a 
narrower needle of the pine. Indeed so great is the range 
of variation that when we regard the larva-like females, it 
becomes difficult to draw the limits between the species. 
Nearly every tree of the orchard and our hard wood, de¬ 
ciduous trees harbor one or more kinds of scale insect. The 
oyster shell scale insect of the apple tree is an unfailing at¬ 
tendant and to young trees is extremely pernicious. The 
orange trees of Florida have been at times grievously afflicted 
by another species, while our ornamental shrubs and vines, 
Fig. 33. 
and hot-house plants suffer greatly from their attacks. The 
injury they do is the result of their vast numbers, since 
they cluster on the leaves and stems of plants, puncturing 
the skin or bark and sucking the sap flowing beneath. 
Happily they have their parasites, certain exceedingly 
small ichneumon flies, such as Coccophagus and Aphelinus 
(Fig. 33 ; 6, antennae, c, larva, all greatly enlarged, after 
LeBaron) which prey upon them. It is not rare to find a 
scale insect with a large round hole in the top of its body, 
through which the ichneumon has escaped. Mites are also 
known to prey upon their eggs. 
The Imported Currant Saw Fly. — This dreadful pest of 
currant and gooseberry bushes affords an excellent example 
of the mode in which an imported animal flourishes far 
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