THE EUROPEAN HORSE-RADISH WEBWORM. 3 
THE EGG. 
The eggs (fig. 2) are deposited in compact masses containing from 
half a dozen eggs to a score or more. 
are difficult to describe, the individual 
egg being scarcely separate from the 
mass. 
The individual egg is irregular oval, the 
mass being arranged more or less irregularly, 
as in the case of a honeycomb. The color is 
a little brighter green than the leaf on which 
it is deposited and each egg is surrounded by 
an irregular ring of yellow spots arranged 
in chains numbering about 12 to 18 to an 
egg. There is strong overlapping, so that an 
egg mass resembles, very imperfectly, a mass 
of fish scales. The surface is finely reticulate 
and divided into shining, minute, irregular 
areas much like the surface of leather. The 
diameter is ubout 0.8 mim. 
THE LARVA. 
In the penultimate stage the larva (fig. 3) 
presents an appearance somewhat similar to 
Both the egg and the mass 
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<a ro oi i 4 TR 
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B 
Fra. “*2—Huropean horse-radish web- 
worm: a, Hgg mass in situ on leaf, 
three times natural size; 6b, sec- 
tion of surface of egg, highly mag- 
nified. 
the full-grown larva as regards the arrangement of the piliferous tubercles, 
but the form is more slender and the body tapers more at each end (the head 
being proportionately much smaller). The general color 
Tig. 38.—European 
horse-radish web- 
worm: Penulti- 
mate stage of 
larva. Much en- 
larged. 
of the upper surface is purplish and has the peculiar ap- 
pearance of being split through the middle, due to a wide 
pinkish longitudinal band separating the two parts between 
the rows of piliferous tubercles. The thoracie and anal 
plates are correspondingly smaller and faint yellowish 
brown. 
THE FuLt-Grown LARVA. 
The full-grown larva (fig. 4) is elongate, cylindrical, about 
Six times as long as wide, and tapers slightly toward each 
extremity, especially posteriorly. The general color is 
variable, generally either dull or shining dark slate gray 
above, sometimes faintly bluish. The lower surface is pale 
greenish yellow or yellowish, and the sides are marked 
with a narrow stigmatal line, orange about the spiracles 
and whitish or yellowish near the sutures. The head is 
shining jet black, faintly but distinctly separated, the delta- 
shaped middle portion longer than wide. The thoracic plate 
is piceous, the middle third or fourth paler, sometimes 
yellowish. The abdominal segments are without trace of 
transverse stripes; the piliferous tubercles are large and 
black; two pairs on the first two segments, the remainder 
arranged in groups of three, each side forming a triangle. 
The anal plate is small, dull pale brownish. The sides have 
a row of substigmatal tubercles, one or two on each segment and another row 
midway between these and the legs; the legs are greenish or yellowish. 
The length is 18 mm.; the width, 3 mm. 
Oe I 
