42 
^MEMOIRS OF THE KATIOXAL ACADEMY OF SCIEi^CES. 
The terms “high” and “low” are expressions much misused and inisapi)lied; the terms 
generalized^ or early or primitive; and modified, specialized, or later, are perhaps truer to nature. 
It is not always the highest — i. e., most specialized — forms which are furthest removed from 
the ancestral forms. For example, the Diptcra, especially the Muscidje, are the most modified of 
insects, i. e., the furthest removed structurally from the winged ancestral forms; but the Hyine- 
noptera, especially the wasps and bees, when we take into account the adult stage, are tlie 
“higliest” — i. c., the most specialized — of all insects. 
Tlie life histories of the colossal moths, Telca imlyplienms and Actias Itnia^ are of much interest 
ill connection with this topic, and our remarks should be illustrated by elaborate detailed descrip- 
tions and colored figures, but the essential points may be indicated by the following epitomes. It 
should be premised that the shape of the tubercles and the glandular sete they bear differ greatly 
ill the freshly hatched larva from their appearance .after the first molt:^ 
/ 
RECAPITULATION OF THE 3IORE SALIENT ONTOG-ENETIC FEATURES OF TELEA POLYPHEMUS. 
A. congenital features. 
1. The setm (bristles) of Stage I but little longer than the tubercles, and both truncate and 
distinctly bulbous at tip. 
2. A slight but distinct differentiation in size and color of the dorsal tubercles, those of the 
third thoracic and ninth abdominal segments being of the same size, and larger than those on 
uromeres 1-7, and of a deeper yellow shade. (Stage I.) 
3. The homologue of the “caudal horn” is distinctly double and more deeply divided than in 
any other American genera of Attacinm; each fork about as long as thick. (Stage I.) 
4. Abdominal legs each Avith 24 crokthets — a larger number by G to S than in the other genera. 
(Stage I.) 
5. Each abdominal segment (uromere) with a lateral pair of transverse black slashes in 
Stage I. 
G. The tAVO tubercles in Stage I on the suranal plate slender, papilliform, and api^roximate. 
B. EVOLUTION OF LATER ADAPTATIONAL CHARACTERS. 
1. The lateral pair of black transverse stripes on each uromere nearly or quite disappear in 
Stage I r. 
2. The segments more convex and angular in Stage III. 
3. Appearance of a yellowish lateral oblique stripe connecting the later.al tubercles of the 
lower and upiier row in Stage III. 
4. Appearance of the pale purplish edging of the suranal plate and anal legs in Stage III. 
5. Api)earauce in Stage lY of the pearly spot on the o.utside of the dorsal tubercles. 
The generic characters are mostly assumed in Stage III. 
RECAPITULATION OF THE 3rORK SALIENT ONTOOENETIC FEATURES OF ACTlAS LUNA. 
A. CONGENITAL FEATURES. 
1. Setrn tapering to a point, not bulbous, and finely barbed. (Stage I.) ]\rost of them are 
three or four times as long as the tubercles. 
2. Some larA^m in Stage I with a very broad lateral dark band along the side of the body, 
some without it; no transverse stripes present, but the head in front is twice banded with dark 
brown. 
3. The second and third dorsal thoracic tubercles differentiated in Stage I, being slightly 
larger than the abdominal ones. 
4. On the suranal plate are two rudimentary tubercles, ejich bearing a tuft of bristles. 
5. The dorsal median tubercle on uromere 8 does not show such marked traces of its double 
‘Origin as Stage I of 0, promethea or T, polifpliemm^ but it is more duplex than in P. cecropia, 
^ See Proc. Amer. Acad. Arts aud Sciences. Boston, xxviii, p. 80. 1893. 
