180 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



-E'.W-— " Pale green, subglobose, slightly coucave at the base, sniODth, shilling. Length, SO mm. ; 

 width, 50 mm. Duration of this stage, thirteen days. Laid in small masses on the underside of 

 leaves." (Beutenmiiller.) 



For the description of the early stages of this caterpillar I have not full notes drawn up from 

 living specimens, but have to depend on alcoholic exani])]es of the different stages and the 

 excellent colored sketches of Mr. Hridgham, so that this notice is in part provisional, as we have 

 yet to see the eggs, although one of the commonest caterpillars oil the oak. 



First stdf/e, li(rvajtist hatched. ~Leu<it\i, ~>-C) mm. August 24. Just before the first molt the 

 body is moderately thick and of a pale yellowish tint; the head is brown,' not deep amber, as iu 

 the subsequent stages. The anal legs are decidedly smaller than the other abdominal legs and 

 •somewhat uplifted, or rather extended horizontally. They are slightly retractile, and probably 

 bear a few hooks. The large dorsal hump on the eighth abdominal segment, so characteristic of 

 the genus Symmerista, is already well developed, so that the chief generic characters of the larva 

 appear at birth. The hairs are minute, short, sparse, and very slightly thickened at the end, all 

 of the same length and arising from minute, microscopic warts. The dark dorsal line is only 

 fainlly indicated; the lateral dark brown line well marked, most distinct on the prothoracic 

 segment, interrupted at the sutures, and faded out on the eighth abdominal segment. The large 

 hump on this last-named segment is large and high, but scarcely differs in tint from the rest of 

 the body, though slightly darker. On each side of the ninth segment is a large black comma- 

 shaped spot, the point directed forward and downward, while behind them is a median black dot. 

 There is a broad yellowish spiracular lateral band ; above it a pale, dirty white band, edged above 

 by the lateral, or rather subdorsal, black line; the underside of the body, including both the 

 thoracic and abdominal legs, is whitish. The anal legs bear about six hooks. 



/Second stage, after the first molt. — Length, 6-8 mm. August 27. The head is still very large 

 jn proportion to the body. The hump on the eighth abdominal segment is larger, more pronounced, 

 and orange yellow, sometimes red; the head is dull amber. The dorsal line is now distinct, and 

 the subdorsal line is triplicated on the two anterior thoracic segments and dui)licated on the 



■ eighth abdominal. Behind the dorsnl hump there are two, instead of one, median black dots, one • 

 placed behind the other, and two black spots are adiled on the side of the body near the base of 

 the anal legs, i. e., two on the ninth and two on the tenth segments. On the pro and mesothoracic 

 .segments are two parallel, short, sinuous, blackish red lines. The spiracular band and underside 



■ of the body asiu the previous stage, but deeper straw-yellow. The anal legs have a longitudinal 

 reddish stripe on the outside or are reddish, near the tip. The hairs are longer and slenderer than 

 before, taper a little, but are docked at the tip, and arise from warts, those on the back arranged 

 in a trapezoid. 



Third stage, after the second molt. — Length, 20 mm. September C. The general shape of the 

 body of the mature larva, with its large, smooth dorsal hump and i)eculiar shining banded skin, 

 is now assumed; the specific cliaracters having apparently now appeared, though we have none 

 of the other forms (albifrons and packardii) with which to compare it. The head is still large, 

 wider than the body, which does not yet grow smaller toward the head as it does iu the fully 

 grown larva. The body is now richly and very conspicuously banded so that already in this stage 

 the caterpillar becomes a very showy object. How it is regarded by birds and ichneumons remains 

 to be observed. The narrow thread-like dorsal line and the lateral line are now inclosed in a 

 broad, dull, whitish-gray band bordered on each side by a faint, dark line. There is a subdorsal 

 straw-yellow broad band. The spiracular deep straw-yellow band is bordered below by a double 

 blackish-red broken line. The dorsal humj) is bright coral red, so bright and conspicuous. as to 

 suggest that when the end of the body is suddenly moved at the presence of an ichneumon the 

 movements of the bright red mass may frighten awaj'the unwelcome visitor. The black spots 

 and slashes on the ninth and tenth segments have increased iu number. The two median 

 reddish black dots of the second stage have coalesced and formed a long strii)e, flanked on each 

 -side by a shorter stripe, and an outer dot on the ninth segment. On each side of the ninth and 

 tenth segments are two blackisii spots. 



Beuteumiiller eayS "jet-black, shiny" (p. 75). 



