214 



MEMOIRS NATIONAL ACADEMY OF SCIENCES. 



Vol. XH, 



to attract the attention of our correspondents as a pest. All of these reports have been verified 

 by specimens."] 



[Strecker in litt. reported S. cecropia from New Orleans, La. Dr. James Fletcher (litt., 

 1900) said it occurred not uncommonly from Prince Edward Island, Nova Scotia, and New 

 Brunswick, up to the western Limits of Ontario, but he did not recall ever having seen a 

 specimen in Manitoba.] 



Life history. 



[The following account of the transformations of S. cecropia appeared in Proc. Amer. Acad. 

 Arts and Sciences, 1893:] 



From some eggs received from Mr. H. Meeske, of Brooklyn, N. Y., the larvae hatched out at Providence during 

 the night of June 14. 



Egg. — It is large, flattened, oval-cylindrical. Length 2.5, breadth 2 mm. The shell is dull chalky white, is seen 

 under a triplet to be pitted, but under a half-inch objective the pits are seen to be in close irregular wavy parallel rows, 



the pits themselves showing a tendency to 

 be grouped into twos or threes. 



Larva. — Stage I: Length when first 

 hatched (June 15), 6 to 7 mm. On emerg- 

 ing from the egg the larva is mostly black, 

 the head, body, and hairs are jet-black, but 

 the tubercles are pale yellowish green, the 

 hairs or bristles they bear being black; the 

 abdominal legs also are pale, the thoracic 

 ones black ; shortly after emerging the larva 

 turns entirely black. One larva was ob- 

 erved drawing itself slowly out of the hole 

 it had gnawed in the egg, having eaten its 

 way through the eggshell at 11.30 a. m., 

 June 15. It was mostly black, but the pale 

 yellowish green tubercles were flattened 

 down close to the body, and the hairs or setae 

 in each verticil or pencil were united in one 

 pencil-like mass and bent to one side on the 

 body. The abdominal legs were pale livid, 

 the thoracic ones black. In 10 minutes more 

 the tubercles had become erect, higher and 

 longer (probably swelled out by the pres- 

 ence of the blood ), and by this time the hairs 

 had assumed their radiate arrangement. 



In one or two minutes more, viz, from 

 11 to 12 minutes after extricating itself 

 from the egg, the tubercles had all become 

 of full length, and erect, and the black 

 setae, or hairs, had now spread out in a 

 verticillate way, as normal. In an hour more the larva had turned perceptibly darker, and in three-quarters of 

 an hour more it had turned entirely black. The spiracles, however, are yellowish green, and thus are rather con- 

 spicuous. The body is stout and thick, the head is as wide a3 the body. On the prothoracic segment are four dorsal 

 tubercles, two on each side of the median line. Along the body are six rows of tubercles, each usually bearing about 

 five radiating se tag; those of the two dorsal series are larger than the subdorsal ones. The tubercles are rather short 

 and stout, fleshy; and are one-half to two-thirds as long as the bristles. The latter are stout, taper to one end, which 

 under a half-inch objective is seen to be blunt, slightly bulbous, and clear, so that these setae are evidently glandular 

 in function; they are slightly rough with rudimentary spinules. On the eighth abdominal segment, instead of two 

 tubercles, one on each side of the median line, as on abdominal segments 1 to 7, there is a single median tubercle, 

 about twice as large round as those on each side, though no higher, and it is evidently the result of the. concrescence 

 in the embryo stage of two tubercles, such as are to be seen on the segments in front. It is transversely broad at base, 

 and also bears 8 or 10 setae, or nearly twice as many as the homologous tubercles on the other segments. The thoracic 

 feet bear at their tips three lancet-shaped flattened acute tenant hairs; while the abdominal legs bear about 16 crotchets. 

 Figure 25 represents the last three abdominal segments; VIII bearing the median double tubercle d', and IX the 

 ninth pair (the right subdorsal tubercle on the ninth segment not being drawn); X the suranal plate with its armature, 

 the two lateral tubercles, bearing each six setae; the tubercles in front usually bear five setse. 



Fig. 25. 



