EXPERIMENT STATION BULLETINS. 



179 



larva is nearly an inch in length. Head and thoracic shield drab, with 

 black markings as shown in the drawing. Along the body is a dark- 

 green dorsal line on each side of which is a very faint almost obscure, 

 dull white line merging to a translucent greenish and bordered by an- 

 other dull white line. On each side is a very obscure yellowish-green 

 line. There is a distinct caudal shield of white and dark-green. The 

 caterpillar is sparsel}' covered with hairs. The moth is reddish-brown 

 on the front-wings and greyish-brown on the hind-wings. Both have the 

 faint markings shown in the drawing." 



REMEDIAL. 



As this insect is rather uncommon and as celery is not a fit plant 

 on which to use the arsenties, it will be best to rely on hand picking. 



m^ 





Fig. 29. — Celery-borer, twice natural size, after G. C. Davis. 



Cut-worms {A gratis c-nigrum et al.) (see Insects Affecting Sweet-corn). 



Zebra Caterpillar (Mamestra picta.) 



For an account of this insect see Insects affecting the Beet. Of course 

 remedies that are used against this insect on beets, would be somewhat 

 dangerous on celery. Hand-picking will ordinarily suffice, and when 

 they are very plentiful, use a spray of one of the non-poisonous emul- 

 sions. 



The Parsley Caterpillar {Papilio polyxenes). 



A common caterpillar on celery, fennel, parsnip, carrot, caraway, etc., 

 is the larva of the black smallow-tail butterfly known in the larval stage 

 as the parsley caterpillar. This conspicuous, naked "worm" is nearly 

 two inches long, green in color, with transverse black bands and spotted 

 with yellow. When disturbed, the larva protrudes a Y-shaped yellow 

 horn, from which emanates a sickening odor, presumably distateful 

 to birds and other enemies. In the pupal stage, the insect is naked 

 and fastened either to the plant itself or to some adjacent object. The 

 butterfly that comes from the pupa, and which is the parent of the 

 larva, is black, measuring when the wings are outspread, from two to 

 three inches across. The outer margins of the wings are crossed by 

 two rows of yellow spots. At the hind angle of each hind-wing is an 



