INSECT ENEMIES OF EASTERN FORESTS 147 
in which a sooty mold develops, giving infested trees a very unhealthy 
appearance. Several species of hymenopterous parasites. as well as 
the ladybird beetle Chilocorus stigma (Say), are reported as serving 
to hold this scale in check. 
The oak lecanium (Lecanium quercifex Fitch) is similar to the 
other scales discussed in this genus. It attacks many oaks throughout 
the Eastern States. 
The spruce bud scale (Physokermes piceae Schr.) attacks various 
species of spruce and is distributed over the Northeastern States and 
southern Canada to Minnesota on the west and Maryland on the south. 
It overwinters in an immature stage on twigs, around terminal buds. 
Kggs hatch in June in Michigan, according to McDaniel (284, p. 22), 
and in July in New York, according to Felt (749, p. 165). The pres- 
Figure 34.—The tuliptree scale (Toumeyella liriodendri) on twigs. 
ence of the scale is most easily determined after it matures, when it 
produces large quantities of honeydew. 
According to McDaniel (284, pp. 21-22), attacks by this species are 
mostly confined to the terminals of the lower branches. Heavy attacks 
may kill branches and cause plantations to assume an unhealthy ap- 
pearance. It is also reported that the black mold, which develops in 
the honeydew, reduces the vigor of the trees. 
Famity DIASPIDIDAE 
The members of this family live under scales composed of the cast 
skins of the previous stages, together with an excretion of the insects. 
The terminal segments of the insect are fused, forming a pygidium. 
The legs and antennae are present in the first-instar nymph, or crawl- 
ing stage, but become atrophied when the nymph settles and feeds. 
The genus Aspidiotus contains several species of scale insects that 
attack forest and shade trees, one of the most important being the San 
