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THE COCONUT SLUG-CATERPILLAR. 
LEPIDOPTERA. 
LIMACODIDE. 
Thosea cinereamarginata Banks. 
Thosea cinercamarginata Banks, Phil. Journ, Sci. (1906), 1, No, 3, p. 229. 
The slug-caterpillar is easily distinguished from other Lepidopterous 
larvee by the form of its body and its mode of locomotion, which is more 
like that of slugs or snails than of insect larva. Several species are 
known in the Philippines, many of them feeding upon palms. In 
Manila, this caterpillar is quite common and is usually found feeding 
either upon the upper or the lower surface of the leaves of the coconut. 
It presents a rather forbidding aspect, due to its being well armed with 
a double series of spinous tubercles placed upon either side, but, as a 
matter of fact, unlike most Limacodide, it possesses no poisonous 
properties. I have handled the larve freely without experiencing any 
discomfort. 
The damage which this insect does to the coconut leaves is about 
equal to that of Padraona chrysozona Plotz. 
Egg—Diameter 1.5 millimeters, height 0.95 millimeters; of a flat, oblate- 
spheroidal shape and with minute reticulations upon the surface, pale-ochraceous. 
The larva escapes through a slit which divides the shell across its face, and the 
latter is not eaten as in the case of Padraona chysozona Plétz. The period of 
incubation is from 5-7 days. 
Larva (Pl. V, fig. 1).—When full grown, length, 23.75 millimeters, width, 
14.25 millimeters including the tubercles. It is pale-green above and pale green- 
ish-yellow at the sides, being almost pure-white beneath, and with the following 
markings: a median, light-purple or heliotrope band with symmetrical scalloped 
margin, the scallops expanding upon the respective segments. The margin of this 
band is darker purple and shades into the green of- the dorsum. The band is 
developed into more or less of a patch upon the fourth and seventh segments, 
where the colors are darker. External to this band, on either side, is a series of 
9 horizontally-projecting, spiniferous tubercles, those upon the second, fourth, 
sixth, eighth, and eleventh being twice or slightly more than twice as long as the 
remaining ones. Below these, ventrally on either side, is a series of 8 light-purple 
spots, one on each segment from the third posteriorly, and below these another 
series of 8 spots beginning upon the 4th segment. At the latero-ventral angle, 
a series of 11 horizontally projecting spiniferous tubercles, one of which projects 
anteriorly and another posteriorly on either side. The spines of these tubercles 
interlace and are yellowish-green at their bases and purple or black at their tips. 
Many of the spines have a white hair at their tips, and the shorter ones at the 
bases of all tubercles have somewhat inflated tips. The head is yellow-green and 
when the caterpillar is not feeding, is retracted within the Ist thoracic segment. 
The length of the larval stage varies from 21-25 days. 
Pupa (PI. V., figs. 2 and 2 A.) —Length 8.5 millimeters, width 5.5 millimeters. 
The color is a light yellow, with ochraceous bands on the posterior margins of the 
dorsal, abdominal segments; the wing pads are livid flesh-color and the eyes are 
dark-gray. 
