764 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
green, ovate, with B small white coronet or raised circular ridge at the top, and some- 
what flattened on the sides that touched each other. 
Tin larva.— The earlier stages did not pass under review, hut there is no reasou to 
suppose that they differ materially from those ahout to pupate, which alone came 
under our observation. Just as the eggs were not laid on the extreme terminal nee- 
m the larva does not commence feeding on the youngest and supposedly the 
most succulent needles, hut on those which form the hase of each terminal fascicle, 
continuing its devastation towards the tip ; hut even in cases where all the needles 
have been denuded, in no case was the terminal hud touched; indeed, the needles 
are only devoured down to the dry sheath which encases their hase. On many treet 
(/// the needles were gone; on many others there yet remained a few of the terminal 
ones, and such trees, as Dr. Hageu suggested, conveyed the idea of immense candela- 
bra. It is evident that many of the larva- pupate on the few remaining needles, 
wheresuch exist, invariably with the head uppermost; hut many forsake the parent 
tree, aud these are prohahly such as have consumed all the food in their immediate 
vicinity. While many larvaB were fouud ascending the trunks of the larger trees, hut 
very few were found descending them, while a large number were seen hanging at 
the end of long silken threads, swaying to aud fro in the wind. Experiments on 
these by Mr. Henshaw and myself fully proved the fact that the larva lets itself 
down from high trees by means of this thread to the ground, abnormal as the 
habit is among the butterflies. In one case, where the thread was fully 50 feet in 
length, I passed my hand beneath the larva to satisfy myself that it was not descend- 
ing a spider thread already woven (of which I had a suspicion on account of the 
great number of threads over the bark of the larger trees), and found no connection 
with the ground. I then caught the thread above and the larva descended gently, 
while swaying in the wind, but detached itself directly it touched the first object. 
Mr. Henshaw obtained the same results. Among the larvae which thus reach the 
ground it is evident that many attempt to regain the upper limbs, for I have found 
several trees which had been girdled by stripping off the bark over a length of some 
four feet, and on such trees several hundred larva) had been caught on the sticky, 
resinous surface thus exposed. Perhaps the most extraordinary circumstance con- 
nected with the change to the pupa was the occurrence of many pupae suspended on 
their threads, in which case the larval skin is shriveled up round the last segment 
of the pupa. 
While the favorite food plant appears to be the yellow pine (Pin usponderosa), both 
Pinus contorta and Abies balsamii were slightly affected, the latter much the least, 
and it is not unlikely that these two trees will form the staple food of the next brood 
in the districts where the yellow pines have been denuded, should it hatch during 
the present season, as is probable. 
Enemies.— The absence of birds has already been noted. May it not be that the 
larva is distasteful to them I As is well known it generally happens in the case of 
native insects that while they may gain a temporary ascendency they are ultimately 
checked by an overwhelming army of parasites, which relegate them to theirnormal 
position in nature. We might thus expect such a thing to occur in this case. 
Whether this natural check may come into play this year or be delayed for several 
years we are not in a position to say. The search for parasitic insects was not pro- 
ductive of either species or numbers. Ichneumonida' were particularly scarce on the 
wing, both round the trees and on adjacent flowers. Indeed, the only conspicuous 
enemy was a large heteropterous insect allied to Pentatoma, which was not uncom- 
mon and certaiuly lived on the larva?, having been taken by myself in the act of 
sucking out the nearly empty llaccid skin. Many such skins were found upon the 
needles and on the ground around the base of infected trees. The numbers of this 
insect, however, were apparently not sufficient to produce any appreciable result. 
Whatever hope is based on relief from parasitic insects, so far as we know at 
present, must rest on the large number of parasitical pupae, although even here the 
