38 
FIRST ANNUAL REPORT OF THE 
longer than broad, their long diameter being now about equal to one-third of the ex¬ 
treme transverse diameter of the old scales. The white appearance of these larvoe I 
found to be due to a white powdery secretion from the general surface of their bodies ; 
which being removed by a moist camel’s-hair pencil, their bodies re-assumed their 
original pale yellow color. As with the larvae of many other Bark-lice and some Plant- 
lice, there were, in addition to this powdery secretion, threads of exceedingly fine, 
liair-like, cottony floss irregularly attached to them, and evidently secreted from the 
general surface of their bodies. At this period, they could without much difficulty be 
detached from the bark by a moist camel’s-hair pencil; but already they had lost 
almost all appearance of organization. Their legs, which only seven days before were 
distinctly articulated and as large comparatively as in ordinary insects, and which then 
discharged all the functions of locomotion with ease, were now almost entirely obso¬ 
lete ; so that even on holding the insect up to the light, under the most powerful Stan¬ 
hope and Coddington lenses, but the faintest traces of legs could be perceived. Their 
antennae had now disappeared altogether. As to any organized beak, I could discover 
nothing of the kind ; but not improbably it might have been inserted in the bark and 
broken off short by detaching the insect from that bark. Motion in this creature there 
was none whatever ; and but for having seen them crawl about with ease only seven days 
before, and knowing that in the course of two or three months almost every one of 
these apparently inanimate scales would generate scores of living white eggs, I should 
never have supposed them to be living animals. On the preceding day, i. e., only six 
days after the general hatch, I had closely examined dozens of them, and could not 
perceive that a single one moved in any way. According to Dr. Mygatt, who says that 
his trees were watched closely by the members of his family, the first bark-louse seen 
to hatch out was on the 23d of May; and after the 27th not one was seen to move. So 
that the process of degradation, by which the animal loses all its locomotive and senso¬ 
rial organs, probably commences about three days after the hatch, and is almost com¬ 
pletely consummated in the space of four days. 
Agassiz lays it down as a universal rule, that “the earliest condition of an animal 
cannot be its highest condition — it does not pass from a more perfect to a less perfect 
state of existence.” (Methods of Study, p. 75.) But here —as also in the case of the 
common Barnacle, which begins life as a highly-organized locomotive crab, and ends 
life by becoming permanently attached like a plant to a ship’s bottom, and by having 
many of its former organs either aborted or degraded — we clearly find an exception to 
what is undoubtedly a general, though not a universal rule. Nor is the exception con¬ 
fined to this one species of Bark-lice. So far as I have ascertained, it prevails univer¬ 
sally throughout two of the commonest genera of the great Family of Bark-lice (Aspi- 
diotus and Lecanium.) 
After this most anomalous and wonderful transformation, the body of the original 
insect grows scarcely at all, the total increase in its length or breadth being only about 
one sixth. But now commences another most strange and anomalous process. From 
the tail end of the limbless and apparently lifeless scale, wdiich is all that remains of 
the once highly-organized larva, there gradually in the course of a few days protrudes 
backwards a thin membranous sack, closely appressed to the bark like the original 
scale, and so far as outline goes forming an elongated continuation of it, but differing 
from it very obviously in color and texture. In 14 days time this elongated sack has 
become in many specimens as long as the original body; and it grows and increases 
backwards at a prodigious rate thereafter, till by the middle of August the whole has 
