Exochorion in the tribe Nymphalini (Lepidoptera: Nymphalidae): the genus Hypanartia Hübner, [1821] and comparison with related genera Author Llorente-Bousquets, Jorge Museo de Zoología (Entomología), Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, México, 04510, CDMX, México & llorentebousquets @ gmail. com; https: // orcid. org / 0000 - 0003 - 0876 - 5333 llorentebousquets@gmail.com Author Nieves-Uribe, Sandra Museo de Zoología (Entomología), Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, México, 04510, CDMX, México & Posgrado en Ciencias Biológicas, Unidad de Posgrado de la Universidad Nacional Autónoma de México, Edificio D, 1 ° Piso, Circuito de Posgrados, Ciudad Universitaria, 04510, CDMX, México & s. nieves. uribe @ outlook. com (corresponding author); https: // orcid. org / 0000 - 0002 - 6497 - 9639 s.nieves.uribe@outlook.com Author Flores-Gallardo, Adrián Museo de Zoología (Entomología), Departamento de Biología Evolutiva, Facultad de Ciencias, Universidad Nacional Autónoma de México, México, 04510, CDMX, México & Posgrado en Filosofía de la Ciencia, Universidad Nacional Autónoma de México, México & emileusher @ hotmail. com; https: // orcid. org / 0000 - 0002 - 3144 - 163 X emileusher@hotmail.com text Zootaxa 2023 2023-08-15 5330 2 151 200 http://dx.doi.org/10.11646/zootaxa.5330.2.1 journal article 10.11646/zootaxa.5330.2.1 2677cbb9-3c7c-4b6b-8467-8745206bbaa2 1175-5326 8253638 35E732D1-4ABB-42C7-A792-B01FADF3AEEA Description of the ridges in the tribe Nymphalini . The Nymphalini are characterized by a specific type of colonnaded ridges ( Table 3 , Plates 16–20 ), which are more derived than those found in Coeini ( Campos-González et al . 2020 ) . They have a low X component (see Plate 2 , Fig. B), leading authors such as Scudder (1889) , Döring (1955) , and Van Son (1979) to describe them as ‘laminar longitudinal ribs’ ( Table 4 ), without the benefit of a microstructural examination using SEM. Because of their low X component in the vertical Y direction, this type of ridge may be related to those found in certain subtribes of Biblidinae ( e.g., Epiphilini, Eubagini ; Nieves-Uribe et al ., 2015 , 2016d ); however, in the latter they are bulkier and more developed. The Nymphalini ridges are not exclusive to the tribe, as the exochorion of Libytheana or Dircenna also exhibits similar-looking laminar ridges (SNU, JLB; pers. obs.). A microstructural examination of the various ridges in the subfamilies and tribes of Nymphalidae is currently in progress. Regarding the other two spatial directions of the colonnaded ridges ( Y and Z axes), we observed variations within the genera of Nymphalini . In some cases, ridges run in the Y direction from the base to a section of the chorion ( e.g ., Hypanartia bella , Plate 6, Fig. A) or reach the cusp, as in the cases of Mynbrenthia , Symbrenthia , Antanartia ( Plates 16–18 ), Hypanartia lethe ( Plates 8 , 9 , Figs. A, Plates 16–18 ), H. godmanii ( Plates 10 , 11 , Figs. A), Aglais , and Vanessa ( Plates 17 , 18 ). In other cases, the ridges run only from the apex to the apical half of the exochorion ( e.g. , Hypanartia dione disjuncta , Plates 12 , 13 ; H. trimaculata autumna , Plates 14 , 15 ; Nymphalis , Polygonia , and Aglais , Plates 17 , 18 ). PLATE 14 . Chorion of Hypanartia trimaculata autumn . A. Lateral view; B. Apical view. i=ridges in colonnade; ii= apical columns overhanging the surface; iii=reduced ridges (beam only); iv=vestigial ’ribs’; v=intercolumnar spacing; vi=basal ribs; vii= projections of the ridges in the transition zone. PLATE 15. Photographs of the chorion of Hypanartia trimaculata autumn under the SEM. A Lateral view.; B. Detail of the colonnades; C. Basal region; D. Apical view; E. Perimicropylar region; F. Micropyle. PLATE 16. Comparative dendrogram of ridges in Hypanartia spp. (redrawn from the cladogram of Willmott et al. 2001 ). Two species of Antanartia have been added. *=hyper-development of the ridges by elongated fusts. PLATE 17. Morphology of the complete ridges of eight genera of Nymphalini . Representations in lateral view. The order of the genera is by morphological proximity of the ridges. PLATE 18. Anatomy of the components of the most apical section of the ridges in eight genera of Nymphalinae . The order of the genera is by morphological proximity of the ridges. TABLE 3. Comparison of some exochorionic characters of various genera of Nymphalini .

Columns
Genus	Ridge projection	Arrangement of the columns	1 shaft 2 beam	Walls	Aeropyles	Ribs
3 rail
Mynbrenthia	the whole	in semi-straight	1 thin and in double arrangement	thick, although	on colonnade	between the
(Plates 17, 18)	chorion	colonnades,	a little thinner in	beams	most basal part
joined by a	2 thick, straight and with minimal	the intercolumns	(coincident with	of the ridges and
basal belt	depressions in the areas where the	capitals), and	the basal belt
aeropyles are	between the
basal ribs
3 thin in part apical with
projections on thick, alternate
plinths; increases in thickness as
you advance to the base
Symbrenthia	the whole	in semi-straight	1 thin and in double	thick, although	on colonnade	subtle at the
(Plates 17, 18)	chorion	colonnades,	accommodation	a little thinner in	beams	poles
joined by a	the intercolumns	(coinciding with
basal belt	2 thick, straight and with minimal	capitals)
depressions in the areas where the
aeropyles are
3 thin in part apical with
projections on thick, alternate
plinths; increases in thickness as
you advance to the base
Antanartia	the whole	in semi-straight	1 thin and double	thick, although	on colonnade	mainly in the
(Plates 16–18)	chorion	colonnades;	a little thinner in	beams	basal pole,
may or may not	2 thick, straight and with minimal	the intercolumns	(coincident with	although they
be joined by a	depressions in the areas where the	capitals), in the	can also be in
basal belt	aeropyles are	lateral basal part	the apical
of the ridges and
3 subtle in part apical with	in the basal belt
projections on thick and alternate
plinths; increases in thickness as
you advance to the base
Hypanartia	the entire	in semi-straight	1 in individual arrangement;	very thin in the	coinciding with	at one or both
(Plates 4–18)	chorion to	colonnades;	elongated in the apical third and	intercolumns or	column capitals,	poles
only the	larger shafts in	tapering towards the base	somewhat thick	(on colonnade
apical third	apical section	and partially	beams)
2 not very robust to slender, with	covering the
slight depressions on aeropyles	shafts
that make it not very sinuous
3 generally subtle and with
projections on the plinths
Nymphalis	only in the	in somewhat	1 in individual arrangement; thick	slightly	on colonnade	present
(Plates 17, 18)	apical fifth,	sinuous	and only conspicuous in fifth	thinner in the	beams and	throughout the
then only the	colonnades	apical	intercolumns	coinciding with	chorion
beam can be	due to the	capitals
distinguished	depressions in	2 thin and very sinuous due to the
the beam	depressions in the aeropyles
3 thin, with bases whose
projections coincide with the ribs

......continued on the next page TABLE 3. (Continued)

Columns
Genus	Ridge projection	Arrangement of the columns	1 shaft 2 beam	Walls	Aeropyles	Ribs
3 rail
Polygonia	maximum	in semi-straight	1 the most apical ones are thin	very thin and	on colonnade	may be present
(Plates 17, 18)	up to the	colonnades;	and there are some couplets; the	only in the	beams; some	or completely
equatorial	some columns	rest are in individual arrangement	intercolumns	do not match	absent
third, after	are very close	and thicken as they approach the	capitals
which only	to each other	equator
the beam	in the apical
can be	region	2 thin, slightly sinuous in the apical
distinguished	and equatorial thirds, and zig-zag
in the basal
3 slightly thickened, without
projections of the plinths
Aglais	maximum	in semi-straight	1 single arrangement, although	very thin and	on colonnade	subtle; in
(Plates 17, 18)	up to the	colonnades; the	some of the most apical ones are	only in the	girders and	apical pole and
equatorial	most projected	slender and in alternate pairs;	intercolumns	coincide with	coincide with
third, after	are in the apical	tapering towards the base	capitals	projections of
which only	third	the plinths
the beam	2 thin and sinuous by depressions
can be	of the aeropyles
distinguished
3 little thickened and much reduced
towards equator; plinths more
projected at apex
Vanessa	throughout	in arcaded	1 in individual arrangement; thick,	very thin and	on capitals;	only in apical
(Plates 17, 18)	the chorion	colonnades	longest in apical section and	only in the	in the most	pole
tapering	tapering towards the base	intercolumns	depressed parts
towards the	of the arched
base	2 thin and forming arches between	beam
the columns
3 absent; the plinths barely project

The projection of the Z spatial direction (radially outwards from the surface of the egg), remains almost constant from one pole to the other in the genera Mynbrenthia , Symbrenthia , and Antanartia ; the ridge, although not very protruding, is conspicuous and remains similar throughout the chorion ( Plates 17 , 18 ). On the other hand, in Hypanartia , Vanessa , Nymphalis , Polygonia , and Aglais , the Z direction is greater in the apical section, and much reduced towards the base. In these genera, the largest ridges (high Z component) correspond to ridges that run more than half of the chorion in the Y direction. Those ridges that run only to the supra-equatorial half in the Y component have a low projection of the Z component ( Plates 17 , 18 ). Hypanartia lethe and H. godmanii ( Plates 8–11 , 16 , 17 , 18 ) show a slightly higher Z component in their supra-equatorial section, as it is slightly reduced towards the basal region ( Plates 8–11 , 16 ). An explanation for these patterns in both spatial components could be found in the oviposition habits, since the reduced ridges (low Y and Z components) correspond to oviposition in clusters ( Nymphalis ) or chains ( Polygonia ) ( Tables 3 , 4 ; Scudder 1889 , Van Son 1979 ). This pattern is similar (analogy) to the reduction of the knolls in Hamadryas species with chain oviposition ( e.g ., H. amphinome , H. fornax ; Nieves-Uribe et al . 2015 , 2019 ). However, further study is needed to determine whether this possibility applies to all cases of reduced ridges ( e.g. , Hypanartia dione disjuncta , H. trimaculata autumna ). Thickened ribs at the basal region are visible in Hypanartia ( Plates 4–16 ), while Polygonia , Aglais , and Vanessa lack conspicuous ribs in this section. The genus Nymphalis is the only one, so far known, that exhibits ribs throughout the chorion, albeit subtly ( Table 3 , Plate 17 ). TABLE 4. Descriptions of the exochorion in selected publications. The present table shows the chorionic data in the works of Scudder (1889) , Döring (1955) , and Van Son (1979) of taxa currently considered as Nymphalini . In the cases of nomenclature shifting, we use the identity symbol (=) to introduce the valid name. We decided to present separately the descriptions of the same species by different authors, since the description would correspond to specimens distributed in the Nearctic ( Scudder 1889 ), Palearctic ( Döring 1955 ), and Ethiopian ( Van Son 1979 ) regions. This table follows the original terms of the three authors. The information contained in those works is limited, with short descriptions mainly focusing on aspects such as size, color, and oviposition habits. Also, the lack of use of techniques to increase the visualization of the exochorionic characters ( e.g. , methylene blue staining, or SEM) prevented a correct identification and discernment of the axes and ridges, with few cases where the latter are mentioned. If we consider ‘laminar axes’ as poorly described ridges, the presence of this character can be verified in almost all genera of Nymphalini .

Taxon and reference	Shape and size (h * w; in mm)	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
Tribe Vanessidi	compact	few, very prominent,	singly or in masses
( Scudder 1889 )	sharp longitudinal ridges, highest on the summit
Antanartia s. schaeneia	0.9 * 1.0	Pale green, darkening slightly later	14–15 longitudinal ribs	40–45 cross- braces	singly
( Van Son 1979 )
Antanartia hippomene	0.9 * 0.6	pale watery green	10–11 glass-like longitudinal	27–31 transverse ribs that	singly
( Van Son 1979 )	ribs	cross- braced the longitudinal ribs
Araschnia levana	almost barrel- shaped; outline top	bright green, the upper part is lighter	8–10 negative petals	few rows of irregular negative	14 whitish ridges without	22 transversal ribs, only the upper	flat or troughed	columns
( Döring 1955 )	view wavy	network	ribbing and disappear at	ones are well developed
0.67–0.72 * 0.52	the base

......continued on the next page TABLE 4. (Continued)

Shape and
Taxon and reference	size (h * w; in	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
mm)
Eugonia =	barrel shaped	7–8	very	in a single
Roddia	with rather	compressed	numerous	compact
tumid sides	laminated	and crowed,	mass, one
( Scudder 1889 )	vertical ribs,	distinct,	layer deep
which start	raised cross
near the	lines
base and
constantly
increase
height, but
scarcely so
high as other
genera
Euvanessa =	somewhat	nearly	broad,	few rather	delicate	broadly	clusters
Nymphalis	barrel-shaped	uniform,	distinctly	prominent,	raised crossed	docked and
crowded,	marked,	compressed,	lines	externally
(Scudder,	roundish cells	only slightly	regular,	rounded
1889)	convex	equidistant,
longitudinal
ribs; increase
in height a
little
Euvanessa	0.88 * 0.74	pale	central circle	very large,	7–8 laminate	delicate	clusters
antiopa =	olivaceous	followed	transverse,	pellucid ribs	transverse
Nymphalis	yellow,	by 2 series	polygonal or	lines, which
antiopa	change	of rounded	hexagonal	become more
to dark	polygonal	cells, often	prominent
( Scudder 1889 )	yellowish	cells	stretching	on either
brown,	across from	side of the
and before	one rib to	ribs, forming
hatching to	another	support
inky black	‘buttresses’
Vanessa	elliptical;	light green,	7–8 petals	2 irregular	flattened	8–9 ribs, run	over 40	flat	large rings
antiopa =	circular	immediately	leaf collars	straight and	transverse	around
Nymphalis	with serrate	change to	goes thinner	ribs, often	willow
antiopa	outline in	light orange	to the base	very delicate	branches
apical view	and becomes
( Döring 1955 )	grey brown
0.9–0.95 *	with a violet
0.7–0.8	shimmer near
hatch
Vanesa	half to three	green,	12 petals	2 leaf collars	9–10 ribs	30–40	flat or
polychloros =	quarters	finally black	of tender	starting at	transversal	troughed
Nymphalis	elliptical;	with white	leaves	the apex as	ribs, the top 5
polychloros	jagged outline	structures	a high ridge	hare slightly
top view	and disappear	further apart
( Döring 1955 )	at the base
0.8–0.9 *
0.7–0.8

......continued on the next page TABLE 4. (Continued)

Shape and
Taxon and reference	size (h * w; in	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
mm)
Vanessa io=	elliptical;	glassy	6–7 petals	leafy	flattened	7–9 ribs that	up to 10, only	rounded
Inachis io	circular	light green,	faint at the	in the upper	edges
with serrate	discolored to	base and	part
( Döring 1955 )	outline in	dark green	with deeply
apical view	with black	hollows
micropylar	between
zone, and	them; tall,
finally silvery	narrow, and
gray	watery white
Aglais	broad ovate	narrowly	8–10 strongly	cross ribs	broadly	groups
( Scudder 1889 )	slightly	compressed	slight but	rounded
and	distinct,
prominent	especially
ribs, well	above
arched at the
summit, but
not so high as
Vanessa
Aglais milberti	0.65 * 0.65	pale grass	about of 10	one or two	9–10 ribs, all	confused
green	kite-shaped	rows of	reaching from	heaps,
( Scudder 1889 )	cells around	considerably	just above	of about
a common	larger,	the base to	3–4 layers;
center	angular cells,	summit	an enormous
separated by	number
pretty broad	must be laid
walls	by single
individuals
Vanessa	elliptical;	dark green	7–8 petals on	none	9 ribs that	23–25
urticae =	circular	a flat mound	goes thinner	transverse
Aglais urticae	with serrate	to the base	ribs,
outline in	always well
( Döring 1955 )	apical view	developed;
6–8 in the
0.72–0.75 *	apex are
0.5–0.52	really marked
Polygonia	nearly	broad and	10	delicate cross
spherical, but	nearly flat	‘longitudinal	lines
( Scudder 1889 )	somewhat	ribs’, few
barrel shaped	regular,
straight,
equidistant,
compressed,
and
prominent;
increase in
height as
approach the
summit

......continued on the next page TABLE 4. (Continued)

Shape and
Taxon and reference	size (h * w; in	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
mm)
Polygonia	elliptical;	Garnet	6–7 petals on	none	2–3 rows of	10 white ribs	5 coarse
c-album	circular	greenish,	a mound	network	that form	transversal
with serrate	discolored	high ridges	ribs near
( Döring 1955 )	outline in	to blackish	at the apex	the apex,
apical view	with black	and disappear	and another
micropylar	at the base;	10–11 very
0.8* 0.5–0.7	zone	wavy at their	delicate
flanks
Polygonia	0.85	grass green	central circle,	first irregular	10–13	very faint
faunus	around which	and then	(usually	cross lines,
radiate 8 or 9	pretty regular	11–12	scarcely
(Scuder 1889)	kite-shaped	pentagonal	vertical ribs	elevated
cells	or hexagonal	running from
cells growing	extreme base
constantly	to extreme
larger	summit, and
increase in
height very
gradually
in passing
upward;
strongly
compressed,
very thin and
have a beaded
appearance
from apparent
indentations
where cross
lines strike
them
Polygonia	0.95 * 0.7	dull bluish	somewhat	8–11	very faint	singly or in
interrogationis	green,	narrowed	(commonly	lines	depending
afterward	10), strongly	on columns
( Scudder 1889 )	becoming	compressed	of several,
grayish green	white rides,	as many 5–8
with silver	growing	eggs (3–4 are
reflections	higher toward	the most
summit	common)
Polygonia	short blunt	pale green,	cluster of	little flattened	11 strongly	exceedingly	broadly	piled in
comma	ovate	glistering	nearly equal	compressed	fine lines,	rounded	columns
hexagonal	vertical ribs;	which	varying from
( Scudder 1889 )	0.8mm * 0.7	cells	increase	transverse	2 to 9 eggs
in height	also the ribs	(average
from base to	over 4)
summit; the
ribs are pale

......continued on the next page TABLE 4. (Continued)

Shape and
Taxon and reference	size (h * w; in	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
mm)
Polygonia	0.95	pale greenish	10 laminated	straight,	rounded	singly
progne	(including the	pellucid ribs,	exceedingly
ribs) * 0.81	commencing	delicate,
(Scudder,	at the	scarcely
1885)	base and	raised cross
continuing	lines, visible
of the nearly	on the ribs
the same	only on the
height over	upper part of
the lower	the egg
half, then
increase their
elevation
Polygonia	0.85 * 0.8	grass green	slightly	9 strongly	exceedingly	broad
gracilis	flattened	compressed,	fine lines
very slightly	which
( Scudder 1889 )	elevated,	transverse
pellucid,	and striate the
vertical	ribs
ribs which
increase in
height from
the middle to
the summit
of egg
Vanessa	very short	few,	a little to	few very	numerous	broad and	individual
ovate;	comparatively	a broadly	prominent,	delicate	rounded
( Scudder 1889 )	transversely	large, pretty	rounded	greatly	transverse
circular	uniform,	compressed,	lines
roundish cells	longitudinal,
regular, and
equidistant
ribs; increase
in height to
summit
Vanessa	0.74	delicate green	minute	transversely	9 laminate	delicate	singly, not
( Pyrameis )	(including the	central cell,	oval cells	pellucid ribs,	transverse	very firmly
atalanta	ribs) * 0.6 (at	surrounded by	with tolerably	start at the	lines, only	attached,
( Scudder 1889 )	the base)	a network of	broad walls,	sides of the	minutely	perhaps
nearly equal	arranged	base and	raised above	owing to the
subcircular	irregularly in	leaving a free	the surface	numerous
cells	about three	space at the	excepting	hairs on the
concentric	summit	when	leaves, but
rows	transverse	seem to cling
the ribs;	by a corner or
here they are	any part that
more distinct,	touches any
especially	portion of the
above, being	leaf or hairs
thickened at
the edges

......continued on the next page TABLE 4. (Continued)

Taxon and reference	Shape and size (h * w; in mm)	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
Pyrameis atalanta = Vanessa atalanta	elliptical; circular with serrate outline in apical view	Juicy green, discolored to dark green	6 very irregular petals	none	10–11 ribs	faint if present at all
( Döring 1955 )
0.7 * 0.5
Vanessa ( Neopyrameis ) cardui	0.75 * 0.58	uniform pale green	cluster of a dozen or two roundish polygonal	14–19 ribs, majority of cases are 16; very thin	faint and delicate cross lines which cross the ribs	singly
( Scudder 1889 )	subequal cells; smaller at the center	and hardly increase in height until the summit is reached	as well as the general surface
Cynthia = Vanessa	barrel-shaped	numerous longitudinal ribs	transverse ribs that cross-
( Van Son 1979 )	braced the longitudinal ribs; more distinct in the upper part of the egg, but well-marked throughout the length of the ribs
Pyrameis cardui = Vanessa cardui	elliptical; circular with serrate outline in	apple green	7–8 petals, lies somewhat raised	none	16 ribs	faint if present at all
( Döring, 1955 )	apical view
0.7 * 06
Cynthia cardui = Vanessa cardui	0.7 * 0.6	pale watery green and only darkens slightly until	16–18 longitudinal ribs	21–25 cross- braces in the longitudinal ribs; faint	singly
( Van Son 1979 )	the dark head forms inside	lower down the side of the egg

......continued on the next page TABLE 4. (Continued)

Shape and
Taxon and reference	size (h * w; in	Color	Rosette	Wreath	Apex	Axes	Ribs	Base	Oviposition
mm)
Vanessa	short ovate	delicate	in a saucer-	slightly	13–16	delicate cross	broadly	singly,
( Neopyrameis )	yellowish	shaped	convex	laminate	lines, which	rounded,	sometimes
huntera =	0.58 * 0.53	green	depression;	pellucid	transverse	scarcely	laid upright,
Vanessa	about 12	ribs and	also the	flattened	quite as
virginiensis	pentagonal	increasing	vertical ribs	frequently in
cells growing	in height	an inclined
( Scudder 1889 )	very gradually	from below	position, but
smaller	to upward;	always very
toward the	turn upward	carefully
center	and at the	tucked under
crest cause	the flossy
the ribs to	hairs which
become very	cover the
distinctly	surface of the
serrate,	leaves
especially
above, but
giving them
a beaded
appearance

In colonnades with beams, a wall covers them, which can be so thick that it is difficult to distinguish the ridge components ( e.g ., Mynbrenthia hippalus , Symbrenthia hippoclus , Plate 17; Hypanartia trimaculata autumna , Plate 15, Fig. B). Alternatively, the intercolumnar wall may be thinner in the intercolumns, resembling windows ( e.g ., Hypanartia dione disjuncta , Plate 13, Fig. B; Antanartia delius , Nymphalis antiopa , Plates 16–18 ), or just slightly covering them ( e.g ., Hypanartia bella , Plate 7, Fig. B; H. lethe , Plate 9, Fig. B; H. godmanii , Plate 11, Fig. B; Polygonia g-argenteum , Aglais urticae , Vanessa virginiensis , Plates 17 , 18 ). The thickness of the ridge wall is related to the distance between the columns, with the thickest walls found where the columns are closest together ( Mynbrenthia, Symbrenthia , and Antanartia ; Plates 16–18 ) and the thinnest or translucent walls where the columns are further separated ( Hypanartia , Vanessa , Nymphalis , Polygonia , and Aglais ; Plates 17 , 18 ). There are two subtypes of colonnade arrangements: double and single. In the double subtype, the columns have plinths that protrude alternatively towards one or the other side of the colonnade, resulting in alternate “ribs” on the chorion and small zig-zag aeropyles on a somewhat thick beam ( Plate 19 , Fig. A). In the single subtype, the columns are thick and have protruding plinths on both sides of each column, resulting in coincident “ribs” and large aeropyles aligned in the same row on a beam of thickness, like the diameter of these ( Plate 19 , Fig. B). The columns in both subtypes have variable girth, which also results in different diameters of the aeropyles. Those of the double subtype have a smaller diameter than those of the single subtype, since the columns in the double subtype are thinner than those in the single one ( Plate 19 ). This is consistent regarding the function of the columns as tubular structures for gas exchange, with the aeropyles at the end of the capitals. When a beam is present, it does not cover the openings and may even have depressions at the aeropyles, forming a wavy ridge (genus Nymphalis , Plates 17 , 18 ) with slight concavities at the aeropyles (genera Hypanartia , Polygonia , and Aglais , Plates 17 , 18 ), to well-marked depressions at these sites ( Vanessa , Plates 17 and 18 ). Regarding the genus Vanessa , they appear to have the greatest specialization and divergence in the ridges. In the species we studied ( Vanessa virginiensis = Vanessa huntera ; Tables 3 and 4 ; Scudder 1889 ), the edge of the ridges is jagged. This may be due to the transformation of the beam of the ridges into arches by shortening the shafts of the columns and depressing them in the areas where the aeropyles are found ( Plate 20 ). This change can be considered an optimization of polypeptidic material by providing better column support without a rail, exhibiting thinner intercolumnar walls, and allowing for better attachment of the egg between the pili of the host plant, requiring less adhesive material by the female, as cited by Scudder (1889) . A more in-depth study within the genus Vanessa is required to corroborate this hypothesis and to consolidate the separation of the genus concerning the number of ridges, as suggested by Scudder (1889) . According to Scudder (1889) , the subgenus Pyrameis has only nine ridges, while the subgenus Neopyrameis has 13 to 19.