13 
“Foreign authors state that in getting its growth this cabbage worm 
moits or casts its skin ‘several times.’ I can say with perfect confi¬ 
dence, it is only three times that it molts. When it first comes from 
the shell it is extremely soft and its skin admits of much distention 
before it constricts the worm to such a degree that it requires to throw 
it off. It is not till it has grown to double its first size and is 0.12 
to 0.15 long that it casts off its skin the first time. It then feeds 
and grows till it has again doubled its size and is 0.25 to 0.30 long, 
when it molts a second time. It again doubles its size and becomes 
about 0.50 long, when it makes its third molt; and the skin which it 
then acquires it retains till it reaches maturity, throwing it off only 
when changing into its pupa form. This is the uniform course of 
these worms, as I have observed in a number of instances. The only 
aberrations I have noticed in these moltings are, that one of them is 
sometimes deferred till the worm is much larger; yet this does not 
appear to affect the other moltings of the same worm, for these occur 
as usual. Thus in one instance the second molting did not take place 
until the worm was 0.38 long; yet the third occurred when it was 
0.53. In another instance the second molting took place when the 
worm was 0.30 long, yet the third was deferred until it was 0.64” 
The almost uniform color is pale green; the full grown larva is a 
little over an inch in length and about one-sixth of an inch in diam¬ 
eter. Dr. Fitch says they are quite uniformly an inch and one-tenth 
in length; but as a general rule I have found them in Southern Illi¬ 
nois oftener nearly an inch and one-fourth in length. The constric¬ 
tions between the segments are not very distinct, but the body ap¬ 
pears rather to be divided into numerous little rings, of which I find 
about six to the segment. They are covered everywhere with fine 
short whitish hairs; interspersed among these are minute black conical 
tubercles or elevated points. By examining closely with a pocket 
magnifier, it will be seen that these black points are arranged^ in rows 
along the transverse ridges into which the segments, as before stated, 
are divided, the intervening, transverse, impressed lines being smooth 
and without hairs or tubercles. 
The head is rather small and is also hairy; the body tapers very 
slightly toward each extremity; there are six true legs, eight abdomi¬ 
nal and two anal fleshy pro-legs. 
The general color, which is nearly uniform throughout, is often de¬ 
scribed as a pea-green; while this is sufficiently correct for general 
purposes,' yet if we examine them closely we find that the green has 
a slightly bluish cast, more apparent on the underside, which is paler 
than the dorsal surface. There is usually a narrow yellow line along 
the middle of the back, but this is sometimes partly obliterated, and 
one now (Nov. 24) before me, and alive, shows scarcely any sign of it, 
a mere trace being visible on the first and second segments, and this 
so faint as to be seen only with a glass under certain reflections of 
light. On each side near the lower margin there is a row of bright, 
yellow dots, one on each segment a little behind the breathing pore. 
When young their skin is somewhat glossy and shining, but when 
they reach maturity the surface assumes a velvety appearance, given 
it by the numerous minute pimples and short hairs with which it is 
covered. 
