568 
Journal of Agricultural Research 
Vol. XXVI. No. II 
ADULT 
The following translation of Zeller’s (9, p. 263-264 , Pl. 3, fig . 18) 
original description has kindly been made by Dr. Adam Boving, of the 
Bureau of Entomology, United States Department of Agriculture. It 
will be noted that the last sentence refers for the most part to the male 
genitalia: 
Head and palpi pure white; terminal joint with two black spots; antennae with 
white and fuscous annulations; fore-wings ochreous gray, spotted with ashy grav. 
Male with anal abdominal segments armed with two lateral clavate projections. 
It agrees with operculella in color of the body parts, only on the head and thorax 
somewhat more gray. Antennae distinctly light and dark annulated. Fore-wing 
ochreous-yellowish gray, dusted over all with gray, so that only ill-defined spots can 
be seen, among which none of the ordinary discal spots or fasciae stand out. The gray 
cilia are darker dusted at the base than in operculella. Hind-wing a trifle broader 
than fore-wing, pointed; below apex a slightly incurved posterior margin. Abdomen 
brownish gray; ventral surface very light, dull yellow; anal segment of the female 
yellowish, longitudinally conical with projecting ovipositor; in the male it is hardly 
as long as the two preceding segments together, the wider side dull ocher-yellow 
haired, forming a half-cylinder on the middle of which above is situated longitudinally 
a thin, pointed, gray, apically light-yellow cone (“ kegel”) (instead of the upper cover 
of operculella); on each side projects over it a thin stylus bent like an S, the yellowish 
end of which is thickened and then pointed and curved like a hook sideways and 
inwardly. 
Habitat: Texas (Belfrage). One good obvious pair; male taken September 18; 
female July 16; in my collection. 
The moth is shown in Plate 1, A. 
Graf (5, p. 12 ), in treating of Phthorimaea operculella as a potato pest, 
states that it has a wing expanse of 12 to 16 millimeters. Adults of 
Ph. glochinella that have been seen by the writer had a wing expanse 
of only 10 to 12 millimeters. They were, however, reared specimens 
and because of this, and the fact that Morgan and Crumb (6, p. 2) found 
moths of operculella reared from potato to be larger than those reared 
from tobacco, it is possible that there is not so great a difference in the 
size of the two species as these figures would indicate. 
EGG 
The recently laid egg is flaccid, dull, translucent white. In shape it approaches 
that of a cylinder with rounded ends. Under the microscope the surface is seen 
to be delicately reticulated. 
Ten eggs gave an average length of 0.343 millimeter, ranging from 0.304 to 0.367 
millimeter, and an average width of 0.193 millimeter, ranging from 0.160 to 0.208 
millimeter. 
LARVA 
The larva (PI. 1, B) is somewhat semicylindrical in shape, the dorsal surface being 
convex and the ventral surface flattened. The body gradually tapers from the first 
abdominal segments to the posterior end and is plainly constricted at the junctures 
of the segments. The head is flattened dorso-ventrally and in living specimens is 
often in part telescoped within the thorax. The surface of the thoracic and abdominal 
segments is dull in appearance, due to the minute, close-set granules with which it is 
covered. There are five pairs of prolegs. 
The newly emerged larva is translucent white except for the head and thoracic 
shield, which in all stages are of a brownish color. Later the larva becomes of a brown¬ 
ish or greenish white, at which time the small dark tubercles, armed with the color¬ 
less setae, are most apparent. Larvae in later stages of development take on a beautiful 
dark blue or dark green color. 
The thoracic legs are light in color. Graf (5, p. 10) has stated that the thoracic legs 
of Phthorimaea operculella are black and in alcoholic specimens (in which the body 
color is lost) of the two species that the writer has seen this difference is very apparent. 
Full-grown larvae measured about 8 millimeters in length. Graf (5, p. 10) states 
that the larvae of Phthorimaea operculella measure from 9.5 to 11.5 millimeters 
when full grown, while Morgan and Crumb ( 6 , p. 4) give their length as from 7 to 14 
millimeters. 
