20 
H. C. AGRICULTURAL EXPERIMENT STATION 
also be carried from one tree to another on the legs and feet of birds, 
although this method must be rather rare. On the whole, the insect 
must rely principally upon favorable winds to spread it from tree to 
tree. 
ENEMIES 
The gloomy scale is subjected to the attacks of a number of enemies, 
the chief one being a small parasitic wasp which attacks the young 
females during midsummer especially. This insect is perhaps the chief 
check on this pest, although there are a number of other parasites that 
prey upon it. It is very difficult to appreciate the good that these para¬ 
sites do, because they are so small and their work is hidden under the 
scale covering. The work of these minute insects may be detected by 
the neat circular holes which they cut through the dorsal scale covering 
in making their escape. 
At least two species of lady beetles, the twice-stabbed laby beetle and 
the pitiful lady beetle, prey upon the gloomy scale to a considerable 
extent. The twice-stabbed lady beetle is much larger and more con¬ 
spicuous than the pitiful lady beetle, but the latter appears to do more 
towards keeping the gloomy scale in control. 
Another group of enemies of the gloomy scale are certain predaceous 
mites. These mites seem to be more scavengers than predaceous enemies, 
but on occasions they have been observed attacking the living scale 
insects. 
Still another enemy of the gloomy scale is the so-called red-headed 
fungus. This disease is always apparent on trees that are badly infested 
with the gloomy scale, and not infrequently it is accused of being the 
real source of the trees’ troubles. 1 his disease does not appear to be of 
much value in checking the ravages of the gloomy scale, for it seems to 
attack the old exhausted females principally. It is usually more preva¬ 
lent on the trunk and larger branches of the tree, where the scale insect 
cannot do as much damage as they do on the smaller branches. 
CONTROL 
Preventatives. Obviously the preventative to be used against the 
gloomy scale is to plant trees that are not usually attacked by this 
insect. The hard maples and the oaks are good shade trees and highly 
resistant to this pest and to most others. Objections are usually raised 
to these trees, however, because they grow so much slower than the soft 
maples*, but when we take into consideration the effects of these insects, 
little seems to be gained, for the persistent attacks of the gloomy scale 
usually stunt soft maples so much that in the long run they do not make 
as satisfactory growth as the hard maples (Fig. 4). When we take into 
consideration, also, that the soft maples are more subject to other dis¬ 
eases, and that they are also more subject to damage during storms, and 
that limbs are more apt to be split off by heavy snows, we can i eadily 
see that there is very little use to plant soft maples. Since nurserymen 
are not always careful to send hard maples when they aie ordered, the 
