ATTACIDES. 275 



Actias (LUNA). — A. Congenital characters: (i) Setae tapering to a 

 point, not bulbous, and finely barbed (stage i), most of them 3 or 4 times 

 as long as the tubercles. 12) Some larvce in stage 1 with a verv broad 

 lateral dark band along the side of the body, some without it ; no transverse 

 stripes present, but the head in front 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, each 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 1 of C. promethea or T< polyphemus, but it is more duplex than in P. cecropia. 

 B. Evolution of later adaptational features : (1) Dorsal tubercles in stage 2 

 higher than before. (2) The lateral dark band disappears in stage 2. (3) In 

 stage 3 the dorsal thoracic tubercles become nearly twice as long and thick as the 

 abdominal ones. (4) The head is not banded -in stage 4. (5) The tubercles 

 brightest (pink or dark carmine) and most conspicuous in the last stage. (6) A 

 distinct infraspiracular yellow line in stage 4, and the suranal plates and anal prolegs 

 lined with yellow, the surface of the suranal plate and sides of anal prolegs amber- 

 coloured. 



We cannot further follow this interesting branch of our subject* 

 and can only deal with some of the more marked peculiarities pre- 

 sented by the early stages of a few Attacid species. The Attacid 

 egg is what we have already described technically as a flat egg. There 

 is considerable difference in detail exhibited both in structure and in 

 the mode of egg-laying, but it may be here noted that the mode 

 of laying around a stem is common to as divergent forms as 

 Hemileuca main (Ent., vi., p. 558) and Saturnia pavonia. Packard 

 gives fProc. Am. Acad. Arts Sci., 1893, pp. 58 et seq.) the following 

 interesting notes on the eggs of various species belonging to the three 

 best-known groups : 



1. ATTACID^:*. — Tlatysamia cecropia: The egg dull chalky-white, pitted 

 in close irregular wavy parallel rows, the pits themselves showing a tendency to be 

 grouped into twos or threes. Samia cynthia : The surface dull, finely pitted (but 

 not arranged in wavy rows as in P. cecropia), the pits near together, slightly poly- 

 gonal, their walls projecting as little bosses on the inside of the shell. Callosamia 

 promethea : The surface pure white, shining, looks (under a half-inch objective) 

 smooth, with only faint, irregular, moderately large, polygonal areas, with faintly 

 raised edges or boundaries. C. angulifera : Same shape and colour as those of < '. 

 promethea, but rather smaller and the polygonal markings even fainter. Actias I ana : 

 Dirty-white in colour ; the surface closely granulated, the pits between the granu- 

 lations often confluent, rarely the raised bosses appear to be polygonal. Telea 

 polyphemus : Chalky-white, with a very broad conspicuous dark brown band, the 

 surface covered with round shallow depressions, bordered with a well-marked rim ; 

 these orbicular areas do not touch each other, there being quite wide spaces between 

 them. 



2. Citheroniid^:. — Dryocampa rubicunda : Thin, parchment-like, smooth, 

 and polished, shows (under \ in. objective) no trace of pits or polygonal areas. 

 Sphingicampa bicolor : Smooth, like parchment, shows (under ^ in. objective) 

 very faint polygonal impressed areas, much fainter than in egg of E. imperialis. 

 Eacles imperialis f : White, with a smooth distinct equatorial ridge, shows (under 

 \ in. objective) shallow pits, not closely crowded, nor with a definite raised 

 edge, often with a boss or bead in centre ; arising from the spaces between the 



* In the Attacinae (sens, strict.) the eggs present generic, specific, and 

 probably varietal, characters (Packard). 



fit is interesting to compare the sculpturing of the eggs of this group, for 

 that of Eacles (imperialis) appears to be intermediate between that of Cttheronia 

 {regalis) and Sphingicampa (bicolor), the shell of Eacles being more distinctly 

 sculptured with irregular polygonal imprints, "which are not so closely crowded as 

 in atheroma (regalis) in the" egg of which the cell imprints are much more distinct 

 and more crowded than in the two other genera (Packard). Bacot describes the 

 egg of Eacles imperialis as being " pale yellow in colour, pearly in hue, semitrans- 

 parent in appearance, like those of the Sphingids and Dimorphids, and not opaque 

 like those of the Saturniids (sens, strict., e.g , Saturnia pavoniaj ." 



