THE BLACKHEAD FIREWORM OF CRANBERRY. 
13 
later in the season, when the vines are maturing, these larvae feed 
principally on the berries, and therefore do more immediate damage 
to the crop if any remains on the vines. 
The result of the work on all three generations is not only the de- 
struction of the current season's crop or its material reduction but 
also the loss of a considerable proportion of the crop the following 
year, the setting of fruit buds being largely prevented by the attack 
of the larvae on the terminals. It will thus be seen that the fireworm 
in one season can very materially reduce the cranberry crop of two 
seasons. 
Fig. 5. 
The blackhead fireworm : Injury of the larvae to the berries, 
the upright is uninjured. 
The large berry on 
Place of Pupation. 
After the larvae have reached their full growth they usually leave 
the webbed uprights and descend to the trash and leaves beneath the 
vines, where they inclose themselves between several old leaves in more 
or less loosely constructed cocoons, typical specimens of which are 
shown in figure 6. Sometimes, however, especially in the case of the 
larvae of the first generation, some may spin themselves up within 
a thin cocoon in the tips of the uprights, as shown in figure 7. Very 
