THE DOCK FALSE-WORM. 9 



Fourth instar. — Length, 9.5 to 14 mm. Dorsum dull bluish green; remainder of 

 body as before. Dorsal surface crossed by whitish lines formed by the wrinkles, and 

 with a scattering of whitish setigerous tubercles. Head light brown, with a dark- 

 brown band dorsally and another crossing the eyes and clypeus. Mouth parts tipped 

 with dark brown. 



Fifth instar.— Length, 14 to 17.5 mm. ; width of thorax, 2 mm. Body of 13 segments, 

 cylindrical, slightly enlarged in the thoracic region. Integument considerably 

 wrinkled, and with a very finely shagreened surface, which gives the larva a velvety 

 appearance. Dorsal region to the line of the spiracles distinct olive green or occasion- 

 ally bluish green; ventral region very light yellowish, color changing abruptly at 

 spiracular line. 



The dorsal olive-green region appears to be crossed by more or less irregular whitish 

 lines, due to the cuticular folds or wrinkles, and laterally this dark region is even 

 darker, as the raised shagreening is black. The dorsal vessel shows through as a dark- 

 green line. The pro thoracic segment is provided with four whitish setigerous tubercles 

 on each side, three of them being in the dark dorso-lateral region and one just above 

 the leg. The other thoracic segments have seven tubercles on each side, having, 

 besides those mentioned above, two near the dorsal line and one latero-ventrally, near 

 the anterior margin of the segment. The abdominal segments, also, have seven 

 tubercles, in slightly different positions, except the last segment, which has only one 

 tubercle on each side of the dorsal line. The anal region is covered with small setae. 



Head narrower than thorax, minutely punctured, sparsely covered with setae, light 

 brown, a dorsal transverse band of dark brown, incised on the dorsum posteriorly by a 

 triangle of light brown, at each side of which is a distinct, short, longitudinal suture. 

 Dorsal part of clypeus, tips of mandibles, palpi, and antennae brown. Eyes very 

 dark brown. Abdominal legs, eight pairs, concolorous with venter; thoracic legs, 

 three pairs, the same but somewhat more heavily chitinized, and with the joints 

 marked by brown lines. 



Sixth instar. — Length, 14.5 to 16 mm.; width of thorax, 2 mm. (length of partheno- 

 genetic larvae, 8 to 12 mm.). Similar to fifth-instar larva in shape and skin texture. 

 Color of dorsal region apple green or pale green; ventral region light yellow. Dorsal 

 vessel showing through whitish or yellowish. No dark contents of alimentary canal. 

 The whitish tubercles have disappeared, but the setae can still be made out in the 

 same positions. 



Head covered with small, irregularly rounded, slightly raised, smooth spots, inter- 

 spersed with raised dots. The spots, when strongly magnified, seem to be made 

 up of two or three cells, this appearance evidently being due to darker markings just 

 beneath the surface. Color of ventral part very light brown, dorsal part, above eye, 

 dark olive brown; clypeus olive brown; tips of mandibles, palpi, and antennae reddish 

 brown; eyes black. 



Prepupal larva. — Length, 6 to 13 mm., average, 10 mm.; male larva smaller than 

 female; cylindrical, somewhat curved dorso-ventrally, shrunken. Body surface 

 wrinkled. Color unchanged. 



THE PUPA. 



Length, male, 7 to 8 mm.; female, 9 to 11 mm. Elongate, slim, the male smaller 

 than the female and more slender. Sexes distinguished by appearance of tip of 

 abdomen, the female saws being very distinct. Dorsal region apple green. Head, 

 appendages, and ventral and lateral surfaces up to spiracular line, light translucent 

 whitish or yellowish, sometimes with a greenish tinge. Eyes reddish brown. 



After a few days the head and thorax become black-brown, and shortly before the 

 adult emerges, the eyes, head, antennae, thorax, and abdominal plates are jet black, 

 the membrane between the plates being light greenish. The legs are light ferruginous, 

 except the metatarsi, which are black, and the distal tips of the protarsi and mesotarsi, 

 which are dark brown. 



56815°— Bull. 265—16—2 



