140 
Vol. XXIX, No. 3 
Journal of Agricultural Research 
SYSTEMATIC DESCRIPTION OF 
PHLYCTAENIA RUBIGALIS 
GUENEE 
For a number of years this American 
species has appeared in our lists and 
literature under the name Phlyctaenia 
ferrugalis Hiibner, on the supposition 
that it was identical with the European 
species of that name. 
On this supposition Fernald (in 
Dyar, 5, p. 887) wrongly listed ferru¬ 
galis as an American species and placed 
rubigalis as one of its synonyms, 
although Chittenden (8, p. 7-26), 
previously had pointed out certain 
differences in the two species. He, as 
well as Slingerland (18, p. 159-164), 
correctly referred to the American 
species as rubigalis Guen6e, following 
Hampson’s (9, p. 242 ) determination. 
A comparison of the genitalia of 
American and European specimens at 
once proved them two different species. 
Phlyctaenia rubigalis occurs through¬ 
out the United States, Central America, 
and South America. As far as we 
know P. ferrugalis does not occur any¬ 
where on this hemisphere. All speci¬ 
mens which we have seen under this 
name from North and South America 
are true rubigalis. 
The two species can be distinguished 
on several characters. Although the 
moths are very similar in size and color 
and difficult to separate with certainty 
without examining the genitalia, the 
outer transverse line on the forewing 
has a slightly different course, being 
more angulate on the costal edge than 
in ferrugalis and more outwardly curved 
on its dorsal half. The faint, oblique, 
dusky shade on the outer fourth of the 
forewing in ferrugalis is hardly present, 
or at least very faint, in rubigalis, and 
the marginal black dots are more dis¬ 
tinct in rubigalis than in the European 
species. 
An examination of either the male 
or female genitalia at once proves the 
distinctiveness of the two species. In 
rubigalis the tegumen of the male 
genitalia is narrower and more elon¬ 
gated than that of ferrugalis which is 
more abruptly shouldered. The dif¬ 
ferences in the anellus are very striking. 
In ferrugalis it is a simple, nearly 
rectangular plate, with two upper 
corners triangularly produced and with 
the incision between these broad and 
shallow; while in rubigalis it is a much 
more ornate structure, with the two 
upper triangular projections much 
longer and the interval between them 
correspondingly narrower and deeper, 
and with two branched and strongly 
scobinated lateral arms. (Compare 
fig. 1, A and B.) 
The harps of ferrugalis are somewhat 
narrower than those of rubigalis and 
contain a cluster of very short, stout 
spines on the sacculus, represented in 
rubigalis by an ill-defined and more 
diffused patch of fine hairs; the clasper 
is stouter in ferrugalis than in rubigalis 
and penis contains only one strong, 
straight cornutal spine, while in rubi¬ 
galis there are. two, one of which is 
curved. Other minor differences on 
the male genitalia are shown in Figure 
1, A and B. 
In the female of ferrugalis the sig- 
num of the bursa copulatrix is consid¬ 
erably broader in proportion to its 
length than that of rubigalis and the 
chitinization around the ductus bursae 
and the genital opening is broader and 
more extended. (For differences in 
detail compare fig. 2, C and D.) 
A single superficial color difference 
at once separates the larvae; in the 
European species there are two distinct 
and conspicuous black spots on each 
side of the thoracic shield, shaped like 
a crude exclamation point, while in 
rubigalis there is only a single elongate 
spot. In occasional specimens this 
may be partly broken up into two, 
but on the whole the character holds. 
A detailed description of the various 
stages of Phlyctaenia rubigalis follows. 
EGG 
Egg 0.8 mm. long by 0.6 mm. 
broad, ovate, flattened, shiny and 
iridescent, whitish when newly laid, 
translucent, surface finely and irregu¬ 
larly reticulated. 
The eggs are generally laid on the 
underside of a leaf, singly or in groups 
of from 2 to 12 or more, overlapping 
one another (PI. 2, B). 
LARVA 
The larva (PI. 2, C, D, E) is slender, 
cylindrical, tapering toward both ex¬ 
tremities; without secondary hair; 
body pale green with a narrow, darker 
