BULLETIN 1336, U. S". DEPARTMENT OF "AGRICULTURE 



Third instar. — Length 8 to 11 millimeters, head width 0.635 to 0.753 milli- 

 meter. Abdomen tapering slightly to caudal extremity, with constrictions 

 between segments moderately deep. Prolegs on fourth, fifth, and last abdominal 

 segments functional. At the second molt the vestigial prolegs on the third 

 abdominal segment entirely disappear. Body chitinizations more elevated than 

 in previous instar, otherwise the same. Setae for the most part long and black. 

 Body shiny j^ellowish-green, dorsal vessel darker green, accentuated by a faintly 

 whitish-mottled border, a narrow mottled whitish stripe on a line just outside 

 the posterior dorsal chitinizations, and another through the spiracles. These 

 white stripes are not found on all larvae in this instar, as individuals vary in this 

 respect. 



Fourth instar. — Length 11 to 19 millimeters, head width 0.886 to 1.166 milli- 

 meters. Body tapering gradually from sixth to caudal segments, moderately 

 constricted between segments. Body shiny yellowish-green, with dark green 

 middorsal line bordered on each side by a mottled whitish line, the narrow 

 subdorsal stripe along the outside margin of posterior dorsal chitinizations more 

 distinct than in preceding instar, and the lateral stripe on a line with spiracles 

 wider, and more distinct than the others. Spiracles appearing as small white 

 dots, those on prothorax larger and showing a fine dark edge. 



Fifth instar. — Length 16 to 23 millimeters, 

 head width 1.306 to 1.586 millimeters. Body 

 widest along first three abdominal segments, 

 tapering slightly toward each extremity. Con- 

 strictions between segments less pronounced 

 than in previous instars, and the three pairs of 

 longitudinal white stripes more distinct, though 

 varying with individuals, head and body other- 

 wise the same. Setae for the most part moder- 

 ately long and dark. Spiracles small, oval, 

 white, with dark edges. 



Sixth instar. — Length 18 to 31 millimeters, 

 head width 1.866 to 2.052 millimeters. Body 

 with first four abdominal segments nearly 

 uniform in width, thence tapering gradually 

 toward each extremity. Constrictions between 

 segments slight. Prolegs functional on fourth, fifth, sixth, 

 and last abdominal segments, pedal hooks 17 to 24. Head 

 (fig. 6) subspherical, flattened, oblique, with emargination 

 at vertex moderately deep; pale yellowish-green, tips of 

 mandibles dark, ocelli black, labrum and outer edge of 

 mandibles distinctly whitish ; face sparsely setose with a con- 

 spicuously long seta near middle of each side of epicranium. 

 Mandible (fig. 7) short and stout, with three distal teeth 

 and one broad cutting projection on inside. Cervical shield 

 with convexity caudad, bearing four long, dark setae inclined 

 cephalad along cephalic margin and four smaller ones along FlG 7 _Mandit>ie of larva 

 caudal margin (fig.8, TI, la, lb, 2a, 2b). Prothoracic spiracle 

 near caudal, margin of segment, oval, white, with dark edge, 



Fig. 6. 



-Dorsal view of head of larva of 

 green clover worm 



of green clover worm 



Fig. 8. — Setal maps of first and second thoracic and fourth, eighth, and ninth abdominal segments of larva 

 of green clover worm: TI, Prothorax; Til, mesothorax; AIV, fourth abdominal segment; A VIII, eighth 

 abdominal segment; AIX, ninth abdominal segment 



