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Psyche 3:147-149, 1880.

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PSYCHE.
FURTHER NOTES ON SOME TINEID LARVAE.
BY VACTOR TOCSEY CHAMBElZS, COVINGTON, KY. (Continued from å´pag 137.)
The regular ratio of growth between
the different stages of these minims would scarcely be believed bv one unfamiliar
with such facts ; thus the lengths of this species (N. pteliaeella) at its several
molts are, as above stated, 0.8, 1.6, and 3.2 mm., and to adopt the language of the anthropologists, its " cranial capacity," as indicated b~- the width of the head at the widest point, is in the different casts of the same larva, 0.0825,0.165, and 0.33 mm.
The mine is a very pretty one ; and sev- eral of them together give to a leaf a very singular appearance. The mines fre-
quently cross themselves and each other, and sometimes almost the entire contents of a leaf are eaten out. There is a similar mine in oak (Quercus) and another in
hickory (Carya) . In these however there is no little blotch at the beginning, the frass is deposited in a central line in the first part (corresponding to the first stage of larval life?), as it also is in the last 12 mm. of the mine, as in this species. This last character is preparatory to leaving the mine to pupate, and does not indicate a molt accomplished, as the other changes in the character of the mine do ; but it is probable that every change in the mode of feeding, and in the character of the
mine, and every decided break in the
continuity of the frass made by a larva
in early life, indicates that it has just completed a molt. Yet there are many
Nepticula mines in which I have not
only failed to find any molt, but also
have failed to find any indication of one. Perhaps the enlargement of the mine of
N. fuscotibiaeella two days before it
ceases to feed may indicate that a molt
then takes place, but I have not found
that its does.
The only cocoons that I have seen
were yellowish green and about 2 mm.
long; they were between the side of
the glass breeding jar and the earth in
the bottom of it. Does it pupate under
ground ?
Aspidisca saliciella Cham. The egg
is deposited usually at the side of the
midrib in willow leaves [Salix] ; the
larva makes a mine just wide enough to
hold it, along the midrib, and 2.12 mm.
long ; here it undergoes its first molt, being at the time 1.06 mm. long. It then leaves the midrib and makes a clavate
mine 3.36 mm. long. when it undergoes




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its second molt, being now 2.12 mm.
the equivalent of the sixth one ia Lib-
long. It then eats out the parenchyma,
wlletis, the fifth also being akipp~d.
making a, small irregular roundish blotch The larva uuflcrgoes another (its from which, it cuts out the little oval
third) molt in its case, after the ease has case in which it pupates.
Its length
been attached for pupation, but previous after it has finished feeding is 4.24 mm. to the molt by which the pupa is formed. The larva hibernates ; in all of its stages, If the case is opened, some days after it except as hercina-fter stated, it is pale has been finally attached, a white silken yellow with a fuscous spot on the under
cocoon will be found inside, fitting closely surfwe of each segment except the head
to the body of the pupa, and the east
and anal segment, and two hairs (one
skin will be found between the cocoon
of them very small)
project from each
and the case. There are therefore four
side of each of the same segments. larval stages. . In the last stage the The body is cylindrical and depressed ; appearance of the larva differs greatly feet are represented (?) by sucker-like
from that of the previous stages. It is
discs, and the trophi from its exit from now yellow, without maculae, and the the egg are of the ordinary form, that is sucker-like spots on the thoracic segments the spinnewt, maxillae and palpi are dis- have disappeared. I have long known
tinct, as well as the other organs. -Each the larva in this condition, but only molt in the mine occupies twelve hours. recently discovered that it attained it It is only recently that I have been able by a third molt, though the difference to follow its life history, haviug formerly in its appearanc'e suggested as much.
supposed that it molted only once.
The Prof. J. H. Cornstock, hi his "Report of width of the head of each cast is, 0.101, the Entomologist- of the V. S . Department U.20-2, 0.303 mm.
I give these figures of Agriculture, for the year 1879," pi. 2, as showing the regularity of the relative fig. '2, b and c, gives figures of these last sizes of the same insect at its different two (or third and fourth) larval stages. molts.
But it will be observed that there The mode of progress in the larvae of are two ratios.
In AspidiKva and ATqt;'- Asptdisca is one 01' the most surprisiug cula the larva in each stage increases its in the insect world. As above stated
length by adding the length of the prece- there are uo true feet or prolegs. ; every ding stage, as 1.06, '2.12, 4.24 mm. and vestige of them has vanished exce[rt on
0.8, 1.6, 3.2 mm. ; whilst in Lithocolletis, the second and third thoracic segments,
Leucuuthwa am1 others the leugtb of the where they are represented (?) by the larva at the eud of its first ataffe is added in little sucker-like discs before mentioned. each of its succeeding feeding stages (U.81, But these discs are not snckers.
They
1.62, 2.43, 3.24, 4.0& mm.). In Aspifiis- axe distinct depressions both ou the ven- ca and others what corresponds t~ the third tral and dorsal surfaces.
They do not
molt of LithocoZletis and others seems to exude any glutinous or other secretion
be skipped, And a double length added
by which the larva gains foothold.
The
at the fourth.
la many larvae there is,
larvae are thus apparently without any
however, a fifth molt, which seems tr~ be means of porgress. Yet encumbered by




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their case, and with the whole body en-
much that there is no reason to suppose
cased except the head and first, and
there is any difference in their histories sometimes the second, segment, they will other than such as relates to size, orna- climb trees and fences, travel through and mentation and food plant. over grass and weeds and irregularities
Antispila, In thisgenus I know the spe-
of ground for distances sometimes of cies nyssaefoliella, cornifolidia, vitiwrdi- many metres before they finally attach folwllu and awpdopsiella in their last and their cases. I was long puzzled to know penultimate larval stages- la their last how they accomplished it, supposing that stage all are fat, white, footless larvae ; the it was by means of the discs, by suction or lirat then having a length of 4.07 mm.
by exuding from them a glutinous secre- when fallr grown, and the last of 3.30 tion. Experiment and observation have mm. In the penultimate stage all hare solved the problem.
There is uo suction the ventriilmaculae on all oftlie segment+ or secretion ; and the discs have nothing except the head and the two hindermost to do with it ; they are not organs of lo- segments of the abdomen. I have never
coxnotion.
The larvae travel solely by seen a mblt in any of the species, but there means of their silk. The head and fol- has evidently heen a molt between the lowing segment, and sometimes the next, two stages above mentioned, and I have are protruded from one end of the case fourid the cnst akin of this molt in the (She larvae sometimes close one eud and
mines. From the size of these two
open the other), then successive taps are stages, and from the size and form of the given with the end of the spinneret to mine, and from analogy with Aapidisca, I the surface on which the lama lies, have no doubt that there is ao earlier molt and thus a minute byssus is formed, to which takes plawin the first three above- which the spinneret adheres ; the body is mentioned species when. the larva is about then contracted BO that the under surface 1.35 mm. long ; and in wnpelopsiella of the case is brought into contact with when it is about 1.1 mm. long. * I know the byssus and apex of the spinneret, the l+rvafi of A. hydraå´ngeaed Cham. and thus the case is attached.
The head and A, Isabella Clem. only in their penal- aud segment's are again extended, and
timate stages. They are very much like
another bysaus is made, and, the body
the other larvae. Isabetla in size agrees contracting, the case is again brought up with viticordifoUelh, and hydrangeaeelkt and attached.
Its attachment is only by
is but tittle larger than ampdopsiella.
a few silken threads each of which is less The mines of all greatly resemble those than 0.0002 mm.
in diameter, and the of Aspidisca, but are larger ; and like fresh silk readily stretches or breaks. nearly all Tineid mines known to me they This is the sole mode of progress of the are at first linear, ending in a blotch which larva,.
frequently obliterates more or less of the I have not followed the changes of
linear part of the mine. They no doubt
A. sphdorife.reUa or any of the species leave their eggs with mouth parts of the other than A, saHsiella; but the mines ordinary form, like Aspidim and Sep- and larvae of at1 resemble each other so tk;da,



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