366 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



inch long, and will be readily recognized from Fig. 308 The 

 beetles hibernate over winter and feed on dock, in the stalks of 

 which the eggs are laid in May. Although eggs are laid in rhu- 

 barb, they fail to hatch or the young larvae die. The grubs 

 become full grown by midsummer and the beetles emerge in late 

 summer and feed a little before entering hibernation. 



Control. As the beetles are sluggish and readily found, they 

 may be easily destroyed by handpicking. Dock plants near the 

 rhubarb patch should be pulled and destroyed in early summer 

 after the beetles have finished laying their eggs, 



The Celery Caterpillar * 



Everyone who grows celery, parsley or carrots is familiar 

 with the large, black-striped, green caterpillar which feeds on 



Q 



FIG. 309. The celery caterpillar (Papilio polyxenes Fab.) : a, full grown larva, 

 side view; 6, front view of head showing extended osmateria; c, male 

 butterfly; d, egg; e, young larva; /, suspended chrysalis about natural 

 size except d. (After Chittenden, U. S. Dept. Agr.) 



their foliage, as it is probably the most common pest of those 

 plants in all parts of the country, ragging the foliage and attack- 

 ing the blossoms and undeveloped seeds. It is the larva of our 

 most common black swallowtail butterfly, shown natural size in 

 Fig. 309. The wings of the male are velvety black with bands 

 * Papilio ^polyxenes Fab. Family Papilionidce. 



