56 WILLIAM T. M. FORBES 



68. Subdorsal Betas of abdomen simple 69 



69. Head rugose, body widest at proleg-bearing segments Lacosomidse (p. 656) 



69. Head smooth, body widest at first segment of abdomen. 



Xylorictidae (Ptoclioryctis) (p. 250) 



70. Prespiracular wart of prothorax with three setae; set iv and v of abdomen 



approximate (fig. 151) QEcophoridae (Ethmia) (p. 244) 



70. Prespiracular wart of prothorax with two setae; setae iv and v of abdomen 



usually distant 71 



71. First and last spiracles twice as large as the others Epiplemidae (p. 654) 



71. Spiracles subequal Thyatiridae (p. 686) 



72. Sete very irregular in length, some ten times as long as others; with obscure 



warts, at least in younger stages, sometimes with spatulate scale -hairs. .73 



72. Setae subequal or supplemented by prominent warts or by spines 74 



73. Labrum notched two-thirds of its depth, or with the notch somewhat shallower 



and continued as a groove to the base of the labrum; North American 

 species with small dorsal hair pencils Eupterotidse (Apatelodes) (p. 678) 



73. Labrum less deeply notched, the notch not continued by a groove; no dorsal 



hair pencils Lasiocampidae (p. 679) 



74. Eighth segment of abdomen with a mid-dorsal horn, plate, or tubercle. ..;. .75 



74. Eighth segment of abdomen not armed in mid-dorsal line 79 



75. Body with numerous branching spines or enlarged tubercles 76 



75. Body with at most two pairs of small spines on thorax 78 



76. Head angulated or spined dorsally, or abdomen with several mid-dorsal spines; 



hooks of prolegs usually triordinal (fig. 27) Nymphalidae (p. 44) 



76. Head evenly rounded; hooks biordinal (fig. 26) 77 



77. A mid-dorsal spine on ninth segment of abdomen; spines of body segments 



strongly unequal, and armed with short nodules or spiracles (fig. 423). 



Citheroniidae (p. 664) 



77. No mid-dorsal spine on ninth segment, or body spines subequal and armed 



densely with long poison -spinules (fig. 418) Saturniidae (p. 668) 



78. Segments with six or eight annulets, prolegs normal in position. 



Sphingidae (p. 42; 360) 



78. Segments with two or three obscure annulets; prolegs unusually widely 



separated Bombycidae (p. 679) 



79. Head high, triangular Sphingidae (Lapara) (p. 42) 



79. Head not triangular 80 



80. An inconspicuous mid-dorsal spine on ninth abdominal segment. 



Citheroniidae (Anisota) (p. 664) 

 SO. No mid-dorsal spines 81 



81. Hooks in an ellipse, at most narrowly interrupted Hesperiidae (p. 43) 



81. Hooks in one band, occasionally interrupted, rarely in two widely separated 



bands 82 



82. Band of hooks reduced or interrupted at middle 83 



82. Principal band of hooks continuous 84 



83. Head half diameter of body; secondary hair relatively prominent. 



Erycinidae (p. 44) 



83. Head rarely more than a third as wide as body; secondary hair less prom- 

 inent Lycaenidae (p. 44) 



84. A forked, eversible dorsal gland just behind head (osmeterium). 



Papilionidae (p. 44) 



84. No osmeterium 85 



85. Body with branching spines, high hairy tubercles, fleshy filaments, bifur- 



cated anal plate or angulated or spined head. Nymphalidae 10 (p. 44) 



> The western Saturniid genera, Agapema and Saturnia, will run here. They have regular, branching 

 spines, strong prolegs, and a small, smooth head, unlike any Nymphalidae known to me. 



