74 A MANUAL OF 



where cabbage was grown the year previous- 

 without finding a single one not infected and 

 spoiled by these maggots. So much reduced 

 has this cabbage pest become by means of this 

 parasite, that if all the worms found while hoe- 

 ing the plants are carefully destroyed, little 

 damage will be done to large plantations, even 

 if no more attention is paid to them. Where 

 but a few plants are set-out in the garden, how- 

 ever, the damage will be proportionately much 

 greater, and if not frequently destroyed, the 

 worms may effect a complete ruin. 



The reason for this is, that the butterflies, 

 which lay the eggs, are very active insects, being 

 almost continually on the wing, and wandering 

 around from field to field. Wherever they can 

 find cabbage they stop and lay a few eggs, and 

 pass on. The consequence is that the eggs, 

 and soon after the resulting worms, become 

 nearly as numerous on the small patch as upon 

 the large, and of course, if there are more 

 worms in proportion to the number of cab- 

 bages, the resulting damage will be correspond- 

 ingly greater. The butterflies are attracted to 

 the cabbage by the sense of smell, and may in 

 a great measure be prevented from finding 

 them in the same manner as we have describ- 



