Article beginning on page 325.
Psyche 5:325-327, 1888.

Full text (searchable PDF)
Durable link: http://psyche.entclub.org/5/5-325.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

THE PARTIAL LIFE-HISTORY OF PSEUDOHAZIS EGLANTERINA, WITH REMARKS ON THE LARVAE OF ALLIED GENERA. BY ALPHEUS SPRING PACKARD, PROVIDENCE, R. I. I am indebted to Prof. C. V. Riley
for the opportunity of examining the
larvae in alcohol of the first stage of this species, which were collected at Mani-
tou, Col. I have carefully compared
these with freshly hatched larvae of Hy- ĺ´perchifi io. When first hatched the
form of the head and shape of the body
are as in H. to, but the larva is some-
what larger. The generic differences
from H. io are confined, not to the
number and arrangement of the spini-
ferous warts, but to the shape of the
spines themselves, and this makes it evi- dent that in prob;ibly all the genera and species of the hemileucini of Grote, the spines themselves are especially devel-
oped at first with reference to the pro- tection of the young larvae, which
huddle together in masses so that their
bodies are protected from observation.
Later in life the spines are smaller in
proportion to the body because more
scattered, and then it is that the larvae are protected by the poisonous nature of the spines, the body itself being more
uncovered and conspicuous. It is just
the reverse of what takes place in the
arctians and other larvae which become
very hairy or bristly late in larval life, and are sparsely provided with hairs
when first hatched. It will also be seen that in respect to the spines the present species when first hatched is much more
highly specialized than H. io, the latter being more simple and generalized a
form as regards the spiniferous warts.
Stage I.-Length 5 mm. The spini-
ferous tubercles arearranged, as in H. io in eight rows, those of the two rows,
one on each side of the median line of the body, and the subdorsal ones being the
larger and longer, while those on the side of the body become shorter and smallei
as they approach the under side of the
body. The spine-bearing warts are
larger and swollen compared with those
of H. io. The dorsal spines on the pro-
thoracic segment* differ from those of
H. io in having the trunk spinulated,
the spinules being long and each bear-
ing a long, tapering hair; the main
spine is pale but ends in two long black forks, each tine of which is 2-3 as long as the trunk of the spine itself, while
the bristle arising from each fork is as long as the latter. The spines of the
two lower rows are spinulate on the
trunk but are pale throughout, while
the larger ones on the back are dark at
the end, being pale at the base. The
dorsal spines on the abdominal segments
* In describing caterpillars it is well, especially in those of bornbyces, to distinguish the three first seg- ments behind the head as the thoracic; the ten succeed- ing ones as the abdominal segments.




================================================================================

differ from those of the thoracic seg-
ments in having a somewhat verticillate
arrangement of the large five or six ter- minal spinules, all being pale except the terminal one, which is considerably
larger than the others.
The single median spines on the 8th
and 9th abdominal segments respec-
tively, occupy the same position as in
H. io, but are larger in proportion and
are not forked as they are in H. io; on
the contrary they resemble spines, one
being larger and darker than the others ; the spine on the 9th segment is a little smaller than the one preceding it.
To recapitulate, it will be seen that
the spinulate spines of Pseudohazis
egZavzterim in stage I are more com-
plicated than those of Hyperchiria io
of the same stage, so that the body is
more concealed from view. The tho-
racic dorsal spines are forked but not so simply as in H. io, while the median
single ones on the 8th and 9th abdomi-
nal segments are not forked but more
or less densely spined in irregular
whorls, with one of the spines larger
than the others.
Fully grow^ larva.-The following
description was drawn up many years
ago from between forty or fifty alco-
holic specimens from the Gulf of Geor-
gia, Cal., in the Museum of comparative
zoology. There was no noticeable va-
riation in the lot. The larva is inter-
mediate in its characters and in size
between Hemilema ma&, which it
more nearly approaches, and Hyperchi-
ria io. The head is smaller than in
either of the two genera mentioned ; in
the thickness of the body it approaches
H. io rather than H. maia. The shape
of the clypeus is much like that of H.
&. The dorsal spines are whorled
as in H. mala. The lateral subdivided
or whorled setiferous spines are longer
than those of the two dorsal rows, but
are not so long as in H. maia. The
arrangement of the longer spines on the
thoracic segments, and on the 8th and
9th abdominal segments are as in H.
mah, but they are shorter, more bushy
and more subdivided. The suranal
plate is triangular lunate. The dorsal
spines are shorter and sharper than
those of H. ma+ being very sharp
and the prick painful even in alcoholic
specimens.
The head, body and spines are black ;
in H. maia the head is reddish, in H. io amber. There is no special coloration
to mark the larva of H. egzasterina,
the body in alcol~olic specimens being
uniformly dark.
Larva of 4th stage. -The larva in
this stage scarcely differs from that in the last stage, the inequality between
the length of the dorsal and upper lat-
eral spines is observed in this stage.
Mr. H. Edwards has described (Proc.
Cal. acad. sci., 19 April, 1875), the
eggs and the mature larva ; he states
that it feeds on Frangda californica
and Rosa. He states that the head is
black, and the body entirely dull black. "Each segment is armed with six lateral
spines, very finely branched, and two
dorsal fascicles of spines, bright chestnut



================================================================================

color, blackish in the centre. The
branchlets of the spines are all bright
chestnut in color. Underside as well
as the feet and abdominal legs dull
black. Length, 2.00 inches."
It is interesting to compare the gener-
ic forms. It is usually impossible to
draw up comparative descriptions of
caterpillars while living, from the obvi- ous fact that one may only have a single species under observation, alive at one
time, and for this reason a collection of carefully preserved alcoholic, as well as of blown specimens is all important;
and I may add that for the careful
study of structural features I much pre- fer good alcoholic specimens to blown
ones, if the caterpillar has been at first killed in very weak alcohol, and, say, a couple of days later transferred to strong alcohol, so that the body does not become too much contracted, and the coloration
faded.
I will now add a description of some
alcoholic specimens of Hemileuca ma&
contained in the Museum at Cambridge,
drawn up as long ago as 1862 or 1863.
They occurred in New Jersey in July
and were compared with Pseudohazis
eglarzterina.
It is larger, the head larger and dark
mahogany in color. There is the same
arrangement of spines, but in H. maia
they are throughout longer than in P.
eglanteha; they are much stouter,
and are paler at the epds. The surface
of the body is marbled with pale flat
tubercles. The underside of the body
is naked, where in P. egla~terina it is
somewhat hairy.
At another time I compared mature
H. maia from Georgia with H. io, with
the following results.
The head in the
two genera is of the same
size, but in
H. &a it narrows towards the vertex.
The clypeus of the latter genus is a little larger, and the sides bulge out rather
than curve in as in H. h, and the sur-
face is more sunken. The body is
rather more elongated and slenderer
than in H. io. There is a median dor-
sal line, and two subdorsal broad bands, dotted with light oval spots in H. maia. The suranal plate is ' elongated lunate, approaching a triangular shape. The
sides of the anal lip are thickened
throughout, more so than in H. io.
Note.-The author would take this
opportunity to say that he is collecting materials for a monograph of all the
Bombyces with 'especial reference to
complete life histories, to be illustrated by colored plates. He is especially
anxious to obtain the eggs of any spe-
cies of Gastropacha as well as the ma-
ture larva, also those of any species of HemiIeuca, Pseudohazis and Hyper-
chiria except those above mentioned,
and also desires the eggs and larvae of
the species of &Zeucoj!~haezq Colora-
dia and @adn'na.




================================================================================