INJURIOUS TO CARROT AND RELATED CROPS 189 



and held in place by a silken girdle around the thorax. The 

 pupal period lasts from nine to sixteen days. There are two 

 broods in the North and at least three in the South. 



In California the black swallow-tail butterfly is replaced as a 

 celery and parsley pest by a related species, Papilio zolicaon 

 Boisduval. 



Control. 



As this insect rarely becomes abundant, it may be usually 

 held in check by hand-picking the caterpillars. 



Reference 

 Scudder, Butterflies of Eastern U. S., 2, pp. 1353-1364. 1889. 



The Celery Leaf-Tyer 



Phlyctcenia fcrrugalis Hiibner 



Celery is occasionally injured by a small greenish caterpillar 

 that folds or webs together the leaves and sometimes bores 



down into the 



stalks. This in- 

 sect is widely 

 distributed in 

 Europe, Asia and 

 North America. 

 In the United 

 States it has 

 been reported 

 injuring celery, 

 spinach and beet 

 but is best known 

 as a greenhouse 



Fig. 114. — The celery leaf-tyer, caterpillar (X 3-^). 



pest, attacking a wide variety of hot-house plants. Its 

 wild food plants include boneset, hedge nettle, strawberry 



