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Psyche 3:135-137, 1880.

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fhyllocnistis. In a former nmero
(v. 3, no. 73, p. 67) I have stated that larvae of this genus molt only twice;
becoming pupae at the second molt.
This statement was the result of careful examinations of namerow mines and
larvae, but since it was made accident
has revealed what careful observation
failed to discover. A short time since I observed in a mine a, larva with the an- terior segments ao much swollen as to
give the larva the appearance of a small paddle, and on removing it from the mine I found that it was in the act of molting. 'There are therefore three molts in this genna. This larva was only one-third
grown, measuring only about 1.3 nun. in
length, whereas the mature larva measures shout 3.9 mm . , but there is no intervening molt, as firequent and careful observation has shown beyond a doubt. There may
be an earlier molt, but if so I have failed to find any indication of it ; if there is, then according to the regular ratio which obtains in the sizes of allied genera the larva ought then to be 0.65 rom. long.
These larvae, and those of moat other
leafaoiners, are translucent, and filled with the green parenchyma in which they are
embedded, ao that in their younger stages it is not only almost impossible to know whether or not they are molting, but it is difficult even to detect their presence in the leaf until they are one-third gram-
The full-grown larva, before it assumes
the second form of hophi, has eight
pairs of lateral pseudopodia, which are
membranous, retractile and not armed
with either clam or tentacles ; the first two pairs, placed on the first and second abdominal segments, are smaller than
the others ; there are also two long mem- branous retractile processes at the anal end, which seem to represent the anal
prolegs of lepidopterons larvae. The pu- pal state continues eight days in summer, and the imago hibernates. In the last
larval stage the trophi are so much abor- fed that if; is difficalt to tell what orgaua they represent ; they are @mil too dia-
tinctly, ante p. 67. The organa of the
imago can be discovered within those of
the papa on the third day after the latter is disclosed and perhaps even earlier.
Nepticula. "What SB written above as
to the difficulty of observations on young larvae of Phyhcnistis applies equally to the larvae of this genus. Until recently only one larval molt - that by which the pupa is disclosed-baa been known in thia germs. Another, earlier, molt baa, I be- lieve, been observed in a European ape-
cies, and according to my observations
(given below) the number does not 8eem
to be the same in all the species. The
larval life in the mine is too short to




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136 PSYCHE.
allow of more than one molt, though I
be N. fuscotibiaeella. Afterwards I bred find that I formerly limited it too greatly it from willow leaves, recognized the
in stating that it lasted only thirty-aix or identity of the species, and mggeeted
forty-eight hours. It is true that in many that there were two other &%@da which
species it does not continue longer than &o mine willow leaves, one of which,
two or three days after the mine becomes unlike all other known ^ptikda, mines
distinctly visible to the unaided eye ; kt the under surface. The other miner of
there is an earlier period in such cases, the upper snrf.ce still remains ~nk&own, lasting three or four days, when the mine font the miner of the under surface proves can only be discerned by holding the leaf to be S'. få´uscotibiweZia The egg, like up to the light, and examining it with a ail S'eptwu,la eggs that I have eeen, ia a lens, yet even then I have not succeeded dark brown roundish or oval microscopic
in finding any other molt than that speck attached to the surface of the leaf. which discloses the pupa. Thus in
When it is attached to the upper m-
y. fitscotifyiaeella Clem. I have found
face the larva mines in the parenchyma
the larva when its length did not exceed nearest to that surface, but when it is
0.85 nun., and the mine itself was only
attached to the under surface, it mines
1.3 nun- long, and have watched it then
neareat to that, unless it has previously for seven days more until it left the mine eaten through to the upper ride as it fte- to papate and yet have failed to find any quently does early in life. In the latter indication of a molt.
The mine b already
pmt of its larval life the entire parenchy- about 19 nun. long before it becomes
ma is eaten out, so that it cannot then be distinctly visible ; but is no wider than said to be a miner of either surface.
the body of the larva ; its total length The egg of LitlwwIleft's celtisella Cham. when the larva quits it is about 40 mm.
ia deposited on the under surface of leaves The larva is of a pale straw yellow, and of Celtic, but the larva early in life eats when full-grown is about 3.2 mm .
The through to the upper ~in-face and becomes young larva ie embedded in the yellowish a miner of that surface.
With the ex-
green parenchyma and therefore is even
ception of these two species all of the
more difficult of observation than the mine# that I have examined are under larva of Pkyllomis^.'is, which lies hme- the surface to which the egg ie attached, diately beneath the cuticle of the leaf ; and the larva, or imago, leaves the leaf the space mined by it at night, when I through that surface. could not observe it, shows that it had I have alluded above to the fact that it not molted at night. I detected no molt
feeds at night as showing that it could
other than that which discloses the pupa. not then have passed a molt which ea-
Thia species mines the leaves of various ~ped me, but thia habit is not peculiar ~pecies of willow (Salw) .
It was first
by any means to this species. KO leaf-
described by Dr. Clemens from captured
mining larva has ever 'been caught nap-
specimens, and subsequently I described
ping" by me. If they ever sleep they do
it also from captured specimens as .N'.
so either while still . eating or molting or cH-imfuseefJa,, suggesting that it might they take very short cc cat naps." I have



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frequently found them when they were
molt accomplished, it begins to feed
not feeding, but they were either molting, again, leaving its little blotch and making sick., parasitized or alarmed.
an exceedingly serpentine or zigzag track, The cocoon of this species is alightly
packed densely with little green pellets renifbrm, about 2 mm. tong and of a
of frass placed transversely.
The mine
bright golden yellow.
The larval life
is linear and no wider than the body of
does not exceed eight; days in the mine, the larva ; the parenckyma nest to the
and is therefore haif as long as that of under amface is not eaten ; and if the
N. pteliwetla, a new species of which
larva happens to strike a vein in its course the imago is yet unknown. Its food
the mine ceases to be crooked, and passes plant, Ptelia, trifdhfct, called also " Hop straight along the vein. This part of the bush," or " Bush clover." is by no means mine is very distinct from that of the first; abundant in this locality (Covington,
stage, is about 23 mm. long, and it takes Kentucky), at least I have but seldom
the larva three days to make it. Feeding met with it ; but where I have found it
then ceases, and forty-eight hours are
in August, every leaf is always mined by consumedin the second molt, which being
the larvae of this species, and many finished, feeding be* again. At the leaves have as many as forty larvae in beginning of thie molt the larva is 1.6 each. The larva is bright green, the
mm. long, having just doubled its length intestine being filled with blue-green pel- since the first molt. The mine of the
lete looking sometimes almost like indigo. third stage is similar to that of the second, It undergoes two molts while still in the though readily disthguiehable from it by mine, besides that in the cocoon by which being a little wider, and having the trans- the pupa is disclosed. Abundant as are verse rows of fm~s not so (tensely packed the mines, I have never seen the egg even -a little wider apartÌÔan the fraas black on the youngest mines. It seems to be- instead of green, and in the last part of come soon
detached from the leaf and it (for 12 mm. before the end) it is placed lost.
The mine ia at first an oval or ir-
in a central line, and not in transverse regularly roundish blotch about 2 mm. in rows. This part of the mine is so crook- diameter, made by eating oat the paren-
ed that it is impossible to give ita length chyma mound the spot at which thelarva
accurately, bat it ia more than 75 mm.
enters the leaf and the entire parenchyma long, and that of the whole mine is not
5 eaten out.
About three days are con- far from 110 mm., or twice as pati as in making this part of the mine, that of 3S'. ft(sc0tibiaeeZ~u. No molt bat as it waa already begun in each in-
occurs in this part of the mine, which is 8i&bn* I cannot be more exact as to the made in six dap, equal to the other two time.
The larva is now 0.8 mm. long ;
stages combined, and making the larval
it ceases to feed and undergoes its first life in the mine sixteen days-about twice molt. This occupies not less than forty - that of JV. faswtibiaselZa,. The length eight hours ; I cannot be more exact of the larva at the end of this etage is 3.2 because in every instance the molt was mm., just twice what it was at the second either began or ended in the night. The molt. (To be conti*nued on p. 147.)



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