MONOPHLEBUS STEBBINGII. 137 
secretion excreted by these insects. The female larva appears 
to spend from six to eight weeks feeding in this position and 
then descends to the young twigs. Soon after this change 
in position is made a further cast of skin takes place. When 
moulting, or shedding its skin, the latter is ruptured at the 
anterior end of the insect at a horizontal line of cleavage just 
above the insertion of the antenne extending to the first seg- 
ment of the thorax on either side. At the same time the skin 
ruptures from a central point in this horizontal line of cleave 
age down to the end of the thoracic segments on the dorsal 
surface and to the coxe of the first pair of legs on the ventral 
surface. The insect then slowly crawls out of the old skin. 
Consequently on the underside of the discarded skin the black 
empty leg and antennal cases are to be found. 

On the twigs the insects, when numerous, collect in clusters 
and thickly cover the young thin-barked portions ; they also 
descend lower down and gather in knots at wounds or cracks 
in the thicker bark below. The insects are about gth of an inch 
in size when they first descend to the twigs. From now on- 
wards their growth becomes more rapid, at least one more cast- 
ing of the skin taking place, until they mature towards the end 
of March or middle of April. When mature, twigs and branches 
may be seen with 6—g inches of their length covered with white 
clusters of these insects, looking as if encrusted with snow, the 
scales lying one on top of another, often tipped up at an angle and 
resting ona companion below : each has its proboscis firmly 
fixed in the bark and is occupied in sucking up the juices, 
During their whole life they are very active and march about a 
great deal over the tree, and they excrete during the whole of this 
period copious amounts of a sugary secretion. This covers the 
leaves and twigs, clogs up the stomata, and runs down the 
branches, dripping down on to the ground below in enormous 
quantities when the insects are plentiful. The male larva has 
not yet been discovered, but the dimago appears on the wing in 
April, perhaps earlier indry years. Itis not so plentiful as the 
female and fertilizes more than one of these latter. It is an 
active little insect, flying about over the serried masses of 
females or walking over the backs of the thick clusters, Pairing 
