238 MANUAL OF VEGETABLE-GARDEN INSECTS 



larva is dark brown in color, lighter on the back and is com- 

 pletely covered by the large mass of excrement carried on the 

 anal fork. The larva becomes mature in about eighteen days 

 and transforms to a brown pupa with three dark stripes on the 

 transparent prothorax. The covering of excrement is retained 

 during the pupal period, which lasts a week to eleven days. 

 In addition to sweet potato and wild morning-glory, this in- 

 sect occasionally feeds on bittersweet. 



Thk mottled tortoise beetle, Coptocycla signifera Herbst 



This beetle (Fig. 146), which is about ^ inch in length, is readily 

 distinguished from the others feeding on sweet potato by having 

 the disk and the front margin of the wing- 

 covers black, mottled with gold or yellow. 

 The disk of the prothorax is black and 

 contains two yellow spots. The larva is 

 green in color, bluish along the back. The 

 excrement is arranged on the anal fork 

 T. ,.„ ^, ^ in broad masses, sometimes with shreds 



Fig. 146. — The mot- , ' 



tied tortoise beetle extending from the sides. The larva be- 

 ^ ^ ^-^ ■ comes mature in about sixteen days and 



transforms on the leaf to a green pupa marked with a con- 

 spicuous black ring around the first abdominal spiracle. This 

 species is not confined to sweet potato and wild morning-glory 

 but also attacks buckeye and thorn. 



The argus tortoise beetle, Chelymorpha argus Herbst 



This species has been reported as occasionally attacking the 

 sweet potato. It is ^^ to y^ inch in length and varies in color 

 from brick-red to clay-yellow. The wing-covers are marked 

 with thirteen black spots and the prothorax usually with 

 six, arranged in two rows. It has also been reported as 

 feeding on milkweed, sunflower, wild morning-glory and 

 horse-radish. 



