10 



1.— Moth of blackhead cran- 

 berry worm (after Riley). 



half an inch long when full grown, and with a shining black head and 

 neck. The adult is a small moth or "miller" with narrow, dusty- 

 brown wings that measure less than half an inch when expanded and 

 seem much smaller because they are so slight. More closely examined 



the fore wings will be found to have alter- 

 nate light and dark gray-brown shade bands, 

 obliquely arranged as shown in fig. 1. 



The moths first appear on the bogs in 

 early June, continuing until nearly the end 

 of the month, and again late in Jul}^, con- 

 tinuing into August, when they disappear 

 for the season. During the day little is 

 seen of them unless the vines are disturbed, when the}^ flvitter away 

 for a short distance, concealing themselves so closely as to be almost 

 undiscoverable unless the actual point of settling has been noted. In 

 the early evening and until the darkness sets in fullj^ they are on the 

 wing and hover a short distance above the plants like a 

 swarm of mosquitoes. 



Though the moths themselves have disappeared for the 

 season before the end of August, the}^ have left, scat- 

 tered everywhere on the undersides of the leaves, their 

 minute yellow eggs (fig. 2). These eggs are flattened, 

 disk-like, and less than half the size of an ordinary pin 

 head, but their bright j^ellow color makes them easily 

 visible against the green of the leaf, even without a 

 magnifier. There they remain throughout the winter, 

 whether the bog be dr}^ or flowed, and the little cater- 

 pillars hatch from them in spring as soon as the tempera- 

 ture reaches an average of about 60 degrees. Many of the eggs- perish 

 during the winter, but where the vines are uncovered in sheltered 

 spots they hatch out little worms about the time the vines themselves 

 are making a start. For a day or two the worms 

 nibble on the under surface of the old leaves or 

 may even burrow into them and then make their 

 way to the tip of an upright, where they spin 

 together the edges of the new leaves. 



The experienced grower, if he walks among 

 his vines a few days after they have made a start, 

 can tell at a glance to what extent his bog is 

 infested by the closed tips (fig. 3) that are promi- 

 nent because the light undersides of the leaves 

 are visible. In about three weeks from the date 

 of hatching, the caterpillar is full grown, lines the inside of its shelter 

 more fully and closely with fine silk, and changes to a stubby little 

 yellowish-brown pupa (fig. 4). In a week the transformation is com- 



178 



Fig. 2.— a cran- 

 berry leaf, 

 showing eggs 

 of blackhead 

 (after Smith). 



Fig. 3.— First \vfb of larva 

 of blackhead (after 

 Smith). 



