240 
MEMOIRS OF THE NATIO^TAL ACADEMY OF SCIENCES. 
Two youug witli horns exactly as in PL XXXII, figs. 2, 2a, were found ou the maple August 
20-29; one of them molted August 27, and tlieu ai>pea[-ed as in PL XXXII, figs. 3, 3a. When first 
found they were stretched out motionless along the midrib on the underside of the leaf. 
In the last stage the larva difiers from that of H, guttivitta in having the three pairs of 
lateral sere brown patches, the difference being simply colorational rather than as regards the 
armature. 
The hint stage , — Length, 30 mm. The head is still high, bilobed, narrowing toward the vertex, 
with two black lines in front extending from each side of the clypeus and ending on the vertex 
near the. tubercles, and another behind one on each side extending from the anteiinm and 
mandibles back halfway nj) the back side of the head. 
The antlers of the early stage are now replaced by two high, conical, rounded, polished knobs, 
each bearing a minute bristle, and from them on the inside two parallel lines extend backward. 
The anal legs are 'Shorter than in the early stage, being about as long as the well-rounded 
supraanal plate. Doubleday probably gives the characteristic attitude of this caterpillar when 
not walking, its legs being moderately elevated, 
I add a fuller description of this larva when fully grown. 
Mature larva , — Length, 35 mm. Head high, narrowing from below to the vertex, which is 
very slightly bilobed. Two black lines ascend from the antenna; and approach each other on the 
vertex, the space between the lines slightly roseate; outside the head is light uniform brown with 
a slight greenish and lilac tinge; the clypeus is small, while the median suture of the epicranium 
in front is very distinct. On the iwothoracic segment behind the vertex are two contiguous, thick, 
conspicuous, large, conical, bright red tubercles, dark at the tip; there are no other humps, aud 
none at the end of the body, which is thickest at and a little behind the nuddle, the body tapering 
gmdually to the long anal legs, which fork widely and are longer than the others, but are constantly 
used. Supraanal plate unusually small. Color of a iieculiar brownish green dotted with black 
l)oints and si}ecks, with a white spot between the prothoracic tubercles. Eody above finely 
marbled with dark brown, with a broken, pale, fiesh-colored line, beginning on the mesothoracic 
segment, and on the first to third abdominal segments suddenly expanding into a large, broad, 
sublozenge-shaped sjmt, suddenly succeeded, over the vsegment beariug the first pair of abdominal 
legs, by a rounded spot. On the top of the fifth segment begins anotlier dorsal patch of the 
same color, which widens and extends down the sides of the third segment from the end. Along 
the middle of this patch are two parallel dark lines; and two broader dark lines of speckles begin 
on the fourth segment from the end of the body, converging and uniting on the second segment 
from the end, forming ou the last two segments a broad median dorsal line. Thoracic legs reddish; 
abdominal legs reddish flesh color. Anal legs slender, reddish. On the oak at Pi^ovidence, 
October 9. 
To recapitulate: 
1. The pair of prothoracic antlers of the early stage of this larva, and those of guttivitta 
ohliqua and nmbrata, is certainly the most unique and unexpected feature to be found among 
Lepidopterous larvm, and the object evidently is to render the creature frightful to its assailants. 
2. The rest of the body is without large horns and markings, the latter of which appear in the 
later stages and are such as to completely adapt it to a maple leaf late in summer or in the autumn 
when portions begin to wither and to turn brown. Hence the horns, if present, would then only 
serve to attract attention to it, and thus they are modified into much less prominent tubercles. It 
should be observed that in the full-grown larva of M, asfarte, which has the same general colors and 
markings as H, guttivitta and H, hiundata, and is thus protected, the jirothoracic tubercles are 
absent. 
How to account for the appearance of such enormous horns may be impossible even after we 
have become acquainted with the early stages of all the allied species, though it should be borne 
in mind that the young of Ciilieronia regalis and Uncles i)nperialis,‘AS^ye\l as Anisota, have nearly 
as large spines when first hatched. 
Ptipa . — Body i^lump; of the same shai^e as in H, guttivitta. Head full and rounded, with the 
two parallel ridges between the eyes slightly larger and more prominent than in H. guttivitta 
