EDW. JACOBSON, BIOLOGICAL NOTES ON THE HETEROGERA. 169 
feeding on Lecanium viride GREEN and by myself as de- 
stroying Lecanium opimum GREEN. 
The observations of ZIMMERMANN, ZEHNTNER and KONINGS- 
BERGER are very incomplete as to the interesting biology 
of this insect. Neither the use of the protective covering, 
nor the construction of the ingenious cocoon seems to have 
been noticed by these observers. i 
As described by Dr. ZEHNTNER the caterpillar always 
carries a protective shield, manufactured out of the empty 
scales the caterpillar has devoured. Large pieces of scales 
closely spun together can plainly be discerned on . the 
shield, which is open from beneath, but at its basal rim 
securely fastened by the aid of silk threads to the branch 
or leave, on which the caterpillar lives. In this way the 
caterpillar is completely shut in and protected against every 
attack. In moving the caterpillar drags the shield a little 
forwards, cuts off the treads, which fasten it to the branch, 
at the same time securing it by new threads. In this way 
the shield is never loose from the branch and the caterpillar 
moves its house slowly along, till it comes upon a scalebug. 
If the prey is still young and flat, the shield is easily 
drawn over it, but if a big coccid is met, the shield has 
to be raised to get the victim partly underneath it. In 
such a case the caterpillar carefully closes the interstices 
between the lower rim of the shield and the branch with 
a dense web of silken threads (See PI. 5 fig. 3.) As soon 
as the shield is drawn over a part of the scalebug, the 
caterpillar gnaws a large hole in its back and devours 
its contents. 
The caterpillar has a very good reason for carrying a 
shield as protection, because the scaleinsects are always 
guarded by ants, which frequent the scales on account of 
their sweet excretions. In the case mentioned, the coccids 
were tended by the fierce red tree-ants Oecophylla smaragdina 
