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Psyche 5:414-419, 1888.

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PSYCHE, [November-December 1890.
homology. It is utterly unphilospho-
cal to accept without the clearest proof such a structural modification as this
change in position of the mandibles
would require, and the modification of
the ordinary labium into a beak of this
character is a process that ought to be
proven. It seems to be assumed that the
bblabium" of the hemiptera is the same
as the "labium" of the diptera, e. g,
Culex, and if this is so, I have a paper now in press, in which I claim to prove
that this bilabium" in the diptera is
really only a modified galea, or a max-
illary structure. I hope to prove some
time in the future, when I can get the
necessary material, how this modifica-
tion of the hemipterous mouth came
about, and that the mandibles do not,
habitually, become internal mouth
structures so long as there are other
organs enough more naturally situated.
Fig. r. S~'i>hoitofiora avenae. a, beak ; 6, bristles of mouth-"mandibles" and "max- illae;" c, antenna of winged viviparous
female.
Fig. 2. Aphis 6rassicae. a, antenna of
wingless forms; 6, antenna of winged vivi- parous female ; c, beak of young lice ; d, beak of mature, winged form.
Fig. 3. Aphis cucumeris. a, antenna of
winged viviparous female ; 6, beak of wing- less forms.
Fig-. 4. Slyaus cerasi. a, 3rd ; b. 5th ; c, 6th joint of antenna of winged viviparous female.
Fig. 5. Aphisfersicae-niger. a, antenna
of immature forms, joints 5 and 6; 6, 3rd; c, 4th ; d, 5th ;
e, 6th joint of antenna of
winged viviparous female; f, sensory pit from fron 1 ; g, same from side.
NOTES ON TWO SPECIES OF DATANA WITH DESCRIPTIONS OF THEIR LARVAL STAGES.
BY HARRISON G. DYAR, RHINEBECK, N. Y.
Of all the closely related species of
this genus, the two which approach
.
each other the most nearly and are most
difficult to distinguish in the imago
state, are D. major and D. drexelii.
I have elsewhere called attention to the main feature by which they are to be
distinguished, which, after all, is only a matter of degree of coloration. The
species differ, or rather tend to differ, in other points beside the brightness of the costal shade, namely, in the more
entire outer margin of the primaries,
and the darker more even coloration of
the wings of D. major.
The size is the same in both species,
there are no markedly distinctive male
genital characters, and the lines and




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November-December ~Sgo.] PSYCHE. 415
spots are arranged in the same manner ;
in fact, there is no absolutely constant difference, either in structure, markings or coloration, between the two so far as I have been able to observe, and I have
no doubt that specimens may occasional-
ly occur which it would not be possible
to refer positively to one species or the other by an examination of the imago
alone. It would at first seem that these species must be more closely related than others in the genus, perhaps hardly
yet distinct; but when we consider the
larval stages, it is at once apparent that they are widely separated, more widely,
in fact, than many other species of Data- na which are readily separable in the
imago state. This difference would seem
to indicate rather a long inherited simi- larity between the moths than very recent derivation from a common ancestor.
While the moths, it may be, have re-
mained constant to their former type,
or undergone a similar development, the
larvae have diverged greatly, which
would seem to correspond to the gen-
eral rule in lepidoptera, that the larvae are often the first to vary. The eggs of D. major and D. drexelii differ markedly :
the larval differences appear in the first stage and are kept up and intensified
throughout the larval period, and only
when the pupa stage is reached, does
the close resemblance observed in the
moths begin. The cause of the diver-
gence in the larvae,especially at maturity, is not very obvious, particularly in the peculiar ornamentation of D. nzajOr,
which differs from that of all of the
other Datana larvae so far known.
D. drexeziz' is abnormal only in the
predominance of yellow about the pro-
thoracic and the 8th, 9th and 10th ab-
dominal segments,* and this might serve
as an excellent protection, in that the
bunches of yellow striped larvae with
their extremities elevated in their cus- tomary position, resemble the little
clusters of
flowers of the Witch-Hazel
with their linear yellow petals, which
begin to blossom in September, just as
the larvae become conspicuous. What
protection, if any, their coloration affords on the Deerberry, their other food-plant, I am unable to say, as they occur almost exclusively on the Witch-Hazel in this
vicinity. (Rhinebeck, N. Y.)
But as to D. major its curious spots
do not resemble anything so far as I can see. It is to be noted, however, that
the habits of the two species differ, for while D. drexeliz' are always gregarious, D. major, when they do not separate
entirely, feed farther apart, and tend to scatter more in the last stage than al-
most any other species, and the change
in ornamentation from lines to spots,
which they undergo in the last molt,
may be of use to them with their
changed habits.
Qg. Sub-pyrifoi-m, of less diameter
and cylindrical for a short distance at the top, recalling the structure of D. i)aZmii; flattened at base or a little hollowed ; evenly flat on top with a sharp angle
between top and sides. Color uni-
form sublustrous white, a rather
* In this article, I have followed the nomenclature used by Dr. Packard for the larval segments, as it is not possible to describe intelligently the markings of Datum by the usual method.




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["November-December 1890,
large central "black spot, larger than
the corresponding one in D. drexelii.
Greatest diameter I. I mm. ; at the top
.7 mm. ; height .7 mm. Laid in groups
of from go to 100 on the underside of a
leaf of the food-plant.
First stage. Head rounded, black,
shiny ; width .5 mm. Cervical shield,
anal plate, thoracic and anal feet and the abdominal feet outwardly, black. Body,
wine red, a very broad subdorsal and
lateral yellowish band nearly entirely re- placing the ground color, and each bi-
sected by a narrow red line. Venter
without marks. A number of hairs
growing from minute dark brown warts.
These warts are proportionally larger in this stage than in any subsequent one.
Hail-s also arise from the cervical shield and anal feet. The larvae at this stage eat the parenchyma of the leaf from above,
and when not feeding, rest on the lower
surface or on the stems.
Secondst+. Head rounded, rather
higher than wide ; shiny black, or with
a slight brownish tinge ; width I. I mm. Body dark wine red, the two pale green-
ish yellow bands on each side as before, very wide, nearly or quite lacking their central lines, so that all that is left of the ground color above is a narrow dor-
sal and subdorsal line. Venter wine
red with a central narrow pale yel-
low line. The hairs from the cervical
shield are long, the others short, aris- ing from minute warts. As the stage
advances, the lateral bands become some- what more distinctly divided by the
ground color and almost white, though
still possessing a yellow tinge. During
this stage and subsequently the larvae eat the whole leaf.
Third stage. Head higher than
wide, narrowing a little toward the ver- tex, depressed at the sutures. Color
sordid orange, becoming red-brown,
the ocelli and mouth parts black.
Width I .6 mm. Cervical shield black
or partly orange ; feet and anal plate
black, shiny. Body blackish brown,
the stripes as before, yellowish white
faintly bisected by a fine line of the
ground color. Venter blackish vinous,
with traces, more or less distinct, of
a central white line. Bases of legs and
corresponding spots on 'the apodous
segments dark wine red, or orange
tinted. Spiracles and the minute pili-
ferous tubercles, black. Hair sordid-
white, short, but a few long ones over-
hang the head. As in the previous
stage, the lines bisecting the lateral bands become more distinct with advanc-
ing growth, the ground color becomes
darker, and the bands clear white. In
many examples, a subventral line inter-
rupted by the bases of the legs and
a central ventral line are to be seen.
Fourth stage. Head . as before,
brownish red becoming darker; the
mouth parts, antennae and ocelli, black ; width 3.1 mm. Body black, with four
lateral clear white stripes on each side, much broader than the intervening
spaces, and three narrow ventral lines
represented in some examples by a few
linear dots only. Cervical shield light
brown, anal plate black or partly brown, thoracic and anal feet and the abdominal feet outwardly black ; bases of legs and



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November-December 1890.1 PSYCHE. 41 7
corresponding spots on the legless seg-
ments brownish red.
Hair white, thin,
longest at the extremities, the ininute
tubercles black.
The lateral bands are
not confluent at either extremity, though in some examples, there is a tendency
for the third and fourth latei al (iibove and before the spiracles) to run together in the middle of the body.
Fifth stage. I in mediately after molt-
ing before the colors have become fixed, the stripes are continuous as in the pre- vious stage, but in a few hours the char- acteristic markings of this stage are
assunled. Head as high as wide,
rounded, shagreened, shiny ; clypeus
wrinkled and depressed in several places, principallyalong the upper part of the SLI- tures ; labrum wrinkled. Color, orange-
brown to almost mahogany. red ; ocelli
black, antennae and palpi ringed with
black and white, their bases red ; man-
dibles black, white inwardly ; maxillae
black. A few hairs sparsely distributed. Width 5.3 mm. Cervical shield, anal
plate, bases of all the legs, and corres- ponding on the apodous segments (i.e.
on the first, second, seventh and eighth, but not on the ninth, abdominal seg-
ments) mahogany red, the thoracic feet
black, the abdominal orange brown, in
some examples a little blackish out-
wardly. Body black, the ventral lines
absent or represented by a few elongated dots, the lateral bands broken into rows of sub-quadrate spots, as I have elsewhere described.* This " serial atrophy " oc-
curt, in the following manner: - the
* Can. ent., v, 21., p. 34.
three upper lateral stripes on each side are broken in each segmental suture
and more or less broadly through the
centre of the segment, the third lateral band (superstigmatal) less broadly than
the others.
The fourth lateral (substig-
inatal) , the subventral, interrupted hy the bases of the legs, and the central
ventral (these last two are represented
only by dots) are broken twice on each
segment, once just before the spiracles
and again toward the posterior edge of
the segment, but are not broken in the
sutures. In some examples, the pos-
terior white spot of the third lateral
band is ag;iin narrowly broken, and the
bisegmental spot of the fourth row
very narrowly in the sutures. The
stigmata1 spot of this row, when large,
is apt to be broken at the spiracles.
01, the prothoracic segment, the two
upper bands are represented by a
white dot behind the cervical shield ;
the third, by a rectangular spot above
the spiracle ; the fourth by the biseg-
mental spot. On the ninth abdominal
segment, the first row has a sub-quad-
rate spot, in some, followed by a dot;
the second, a rectangular spot scarcely
bisected, the third and fourth are
nornlal. The tenth abdominal has
only a dot representing the third lat-
eral band, and the bisegmental spot
representing the fourth. The subven-
tral lines are represented by dots be-
tween each segment from the third to
the eighth abdominal, and the ventral,
by the bisegmental dots and a dot an-
terior to the bases of the legs on the
second to the sixth abdominal segments.




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41 8 ps2THE. [ November-Decem ber 1890.
Spiracles velvety black. Hair white,
rather long, beside numerous fine, short black hairs, all growing from minute
black tubercles. Length of larva at
maturity 60 mm. The form of this
larva with canary yellow bands and
spots did not occur in any of the examples from which these notes were made (a
brood of 55 and another large brood ob-
served in the field). I have formerly
found a few yellow ones among a brood
ofwhite spotted D. major^ and occasion-
ally a brood entirely yellow.
Though
the difference in coloration is very
marked between the two forms, it is
evidently, from its mode of occurrence,
only a variation. A similar variation
occurs in D. $aZmi/ * and less markedly
in D. contracts.
Pupa. Formed in a subterraneous cell.
In shape it is robust, cylindrical, thickest centrally, and rounded to the head ; cases distinct; a slight creased elevation be- tween the eyes. Abdominal segments
slightly tapering ; cremasters, two, very short, not well separated, each with three spines, the posterior one the longest, but often two, or partly aborted. Cases
creased, body coarsely punctured, very
finely in the movable sutures. Color
dark or blackish mahogany. Length 25
mm., width 9 mm. This stage lasts
through the winter and the species is
single brooded. The dunition of the lar- val stages was as follows: - 1st stage,
not observed, but probably about five
*I would like to call attention to the relationship that evidently exists bi-tween D. palmii and D. major, They are alike in egg structure, in the feature of bico- lorous larval hairs (which does not occur in any other species to my knowledge), in coloration of head and lines and in the slightly scalloped forewings of the moth.
days ; 2nd stage, 6 days ; 3rd stage, 8
days ; 4th stage, 9 days.
FOOD-PLANT : Andromeda Zigustri-
m.
Larvae from Ulster Co., N. Y.
DATANA DREXELII, Hy. Edw.
Eyg.
On the type of D. ministra.
Subcylindrical, of a little greater di-
ameter near the bottom than near the
top ; vertex rounded ; base nearly flat. Color shiny whitish, the circular lid-like top very white and shiny, with a central small round black spot.
Diameter .7
mm. In hatching, the larva eats away
the lid, and emerges from the hole thus
formed.
First stage. Head rounded, black,
shiny ; width .5 mm. When newly
hatched, the larva is scarcely dis-
tinguishable from D. major. The
anal feet are rather long and elevated.
Body sordid yellow, cervical shield, anal plate and feet, blackish. A number of
short hairs from the head and from
about six rows of small blackish tuber-
cles which are larger in proportion than in the subsequent stages. As the stage
advances, the body becomes reddish
with four lateral stripes on each side
and three ventral, about as wide as the
intervening spaces, dull yellow and con- fluent posteriorly. During this stage,
the larvae eat the parenchyma in the
same manner as D. major. I have
estimated that a single larva eats about 90 sq. mm. of Witch-Hazel leaf.
Second stage.
Head black and shiny
with a few hairs, width I. I mm.
Body
brown, stripes dull yellow, narrower
than the intervening spaces, extending




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November-December 1890.3 I's2pm. 41 9
from the cervical shield and the anterior edge of the prothoracic segment to the
anal plate and becoming a little con-
fluent there. Cervical shield, anal
plate, thoracic and anal feet and the
abdominal feet outwardly black. Hair
short and pale. During this stage, the
larvae eat the whole leaf.
Third staye. Head higher than
wide, depressed at the sutures of the
clypeus ; smooth shiny black, width
1.8 mm.
Body brown, the stripes yel-
low, confluent posteriorly and along the anterior edge of the protlioracic seg-
ment. Otherwise as in the previous
stage.
Ponrth stage. Head shaped as be-
fore. smooth ; ce~lt~-iill~ depressed at the top of the clypeus and more slightly
along the central suture ; clypeus and
labrum wrinkled ; all shining black ;
width 3.2 mm. Cervical shield black
or partly brown, in some examples
nearly all light brown ; anal pl;ite,
thoracic feet and the abdominal feet
outwilrdly, black. Body black or partly
brown, the anterior half of the pro-
thoracic segment yellow, the stripes
strongly confluent on the last segment.
The bases of the legs and corresponding
spots on the legless segments, as in the mature larva, of a darker yellow than
the lines. Each segment is shaded cen-
trally with this yellow, but it does not cause the lines to appear confluent on
account of its darker shade. Hair sor-
did white beside other short fine brown- ish hair seen with a lens.
Fifth stage.
Head as high as wide,
flattened in front, depressed at the upper part of the sutures of the clypeus, punc- tured. Clypeus and labrum somewhat
wrinkled. Color shiny black, the an-
tenniie and palpi white-ringed, their bases greenish. Width 5.4 mm. Body black,
cervical shield honey yellow, anal plate, thoracic and anal feet and the abdomi-
nal feet outwardly, black. Anterior half of the prothoracic segment yellow;
stripes narrower than the spices, citron yellow, running into the yellow part of
the prothoracic segment and confluent
posteriorly on the tenth abdominal,
which is all yellow except the and
plate and a dorsal band. The three
upper lateriil lines are connected also on the eighth and ninth abdominal seg-
ments by a broad dark yellow shade.
The bases of the legs and corresponding
spots on the apodous segments (on the
first, second, and seventh, eighth and
ninth iibdominal segments) also dark
yellow, foiining expansions of the sub-