LLUSTRATIONS. 



PLATES. 



Page. 

 Plate I. Adults of the sugar-beet wireworm (Limonius californicus), showing 



variation in size 12 



II. Stagesof the sugar-beet wireworm. Fig. a. — Adult. Fig.b. — Newly 



hatched larvae. Fig. c. — Eggs 12 



III. A sugar-beet wireworm in process of molting 12 



IV. Wireworms and wireworm-like larvse 12 



V. Pupa of the sugar-beet wireworm 16 



VI. Injury by the sugar-beet wireworm to germinating beans 16 



VII. Injury by the sugar-beet wireworm to germinating bean, enlarged. . 16 

 VIII. Fig. 1. — Sugar-beet wireworms in petri dish, killed by bacteria in 

 cultures of agar. Fig. 2. — Root cage used in rearing young wire- 

 worms 20 



IX. Work of the sugar-beet wireworm. Young sugar-beets, showing 

 injury by wireworms to taproots; blackened feeding marks visible 



on end of roots 24 



X. Work of the sugar-beet wireworm. Nearly mature beets killed by 



wireworms; blackened feeding marks noticeable on taproots 24 



XI. Work of the sugar-beet wireworm. Mature beets, showing old scars 



resulting from wireworm injury 24 



XII. Ravages of the sugar-beet wireworm. Beet field, showing small 



cleared space resul ting from the work of wireworms 24 



XIII. Ravages of the sugar-beet wireworm. Beet field, showing cleared 



spaces resulting from the work of wireworms 24 



XIV. Ravages of the sugar-beet wireworm. Beet field, showing cleared 



spaces, more extensive than in Plate XIII, resulting from the work 



of wireworms 24 



XV. Ravages of the sugar-beet wireworm. Beet field, showing very large 



cleared space resulting from the work of wireworms 24 



XVI. Adult of the sugar-beet wireworm issuing from pupal skin 32 



XVII. Habits of beetles of the sugar-beet wireworm. Fig. 1. — Beetles of 

 the sugar-beet wireworm in secondary hibernation under slice of 

 sugar beet. Fig. 2. — Beetles of the sugar-beet wireworm photo- 

 graphed while feeding on slices of sugar beet 32 



XVIII. Sec'ondary hibernation of the sugar-beet wireworm. Beet tops used 



by beetles as quarters for secondary hibernation 36 



XIX. Fig. 1. — Field of young beets at age when they begin to be partially 

 safe from severest injury by the sugar-beet wireworm. Fig. 2. — 

 Beet field showing conditions favorable for increase of wireworms. 



Weed hedges which shelter adults in secondary hibernation 60 



X^. Conditions favoring the sugar-beet wireworm. Beet field imme- 

 diately after harvest, showing beet tops carelessly scattered over 



ground 60 



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