4 BULLETIN 190, UNITED STATES NATIONAL MUSEUM 



armature in different, definite arrangements are constant within the species 

 and furnish excellent diagnostic specific characters and, in our opinion, also 

 dependable generic characters. 



The female genitalia have a simple, more or less cup-shaped ostium; 

 the ductus is short, sometimes sclerotized on the terminal part ; the bursa 

 is normally simple, oval, thin-walled, and without signum, but in the 

 Paranthrene group there are fine transverse wrinkled circles around the 

 bursa, and in some forms of this group each wrinkle is slightly more 

 sclerotized in a small dot ; the longitudinal line of these dots constitutes a 

 faint signum; in Sigtiaphora there is a definite signum consisting of a 

 single strong, short spine. 



The pupa has transverse rows of spines on the dorsum of the abdomen, 

 double rows on segments 2 to 6, inclusive, of the female and on segments 

 2 to 7 of the male ; the female has one row on segment 7, and both sexes 

 have single rows on segments 8, 9, and 10; the spines on abdominal 

 segment 10 are broad, and the row extends nearly to the ventromeson. 

 Maxillary palpi present. Wings narrow and pointed. Cremaster absent. 

 Large spines always present on venter of tenth abdominal segment. Pupa- 

 tion normally takes place within the larval burrow. 



The larvae are ivory white and without body markings except for some 

 yellow or yellowish-brown shadings on the thoracic shield ; cylindrical and 

 tapering somewhat abruptly caudally; intersegmental incisions deep; 

 thoracic segments more or less enlarged. Body and head with primary 

 setae only. Body setae inconspicuous, pale, short; three setae on 

 prespiracular shield of prothorax; setae I\^ and V approximate, on a 

 single pinaculum and situated under the spiracle on proleg-bearing abdomi- 

 nal segments; setal group VIII bisetose on first abdominal segment, 

 trisetose and arranged in a transverse line on second abdominal segment 

 and unisetose on ninth abdominal segment; seta lie of prothorax lying 

 between lb and Ic and closer to them than to lib; all setae on ninth 

 abdominal segment arranged in a transverse row, seta V much reduced 

 and usually approximate to III and remote from IV; seta VI frequently 

 reduced, sometimes absent, on ninth abdominal segment. Sclerotized areas 

 about body tubercles very weakly pigmented, inconspicuous. Thoracic 

 legs short. Prolegs of the normal number, but short ; crochets uniordinal 

 and arranged in two transverse bands, sometimes {Bemhecia, Melittia) 

 very small and weak. Spiracle on eighth abdominal segment located very 

 high (subdorsally or dorsally) on segment, considerably larger than other 

 abdominal spiracles. Anal fork absent. 



Larval head appreciably smaller than prothorax ; epicranium with inci- 

 sion of dorsal hindmargin deep and with posterior lobes produced and 

 rounded ; adfrontal sutures reaching to or very nearly to incision of dorsal 

 hind margin; longitudinal ridge short. Ocelli 1, 2, 3, and 4 grouped 

 together, trapezoidally arranged and remote from ocelli 5 and 6. Head 



