CAPE COD CRANBERRY INSECTS 51 



Description and Seasonal History. 



The Eij(j. 



Tlie eggs are sniootli, globular, aixnit a twentieth of an incli in diameter and 

 pale pinkish brown when first laid. They grow darker within three weeks 

 when fertile, owing to the development of the worms. They are laid soon 

 after the moths emerge, mostly in oval or rounded masses of four hundred to 

 sometimes over a thousand (Plate Four, fig. 12). These are half an inch to 

 an inch and a half long and a third of an inch to an inch wide. They are 

 covered with yellowish hairs from the abdomens of the moths and look like 

 pieces of sponge. They are laid in every conceivable place, but the trunks 

 and branches of trees probably are the most natural locations. They usually 

 are placed within a few inches of the pupal case from whicli the moth emerged. 



The young worms become fully formed within three weeks after the eggs 

 are laid. They cannot endure a temperature lower than — 25° F. and often are 

 winterkilled extensively in northern New England. Some hatch in September 

 in rare instances, but they normally appear from the last of April to mid- 

 June, according to the weather and their position, those in warm sunny places 

 coming out earliest while those in cool shady locations emerge much later, 

 most of them usually hatching between the Pith and the 25th of May. 



The winter flowage of bogs does not harm the eggs much as long as it is 

 cold, for they hatch readily afterward if it is let off early in April. If it is 

 held till after May 20, the hatching is negligible. 



The Worm. 



The caterpillars in their first stage are very dark and, being clothed with 

 long hair and provided with aerostatic hairs, are borne easily by the wind. 

 It sometimes carries them twenty miles or more. 



The worms grow rapidly during late May and June and mature in July. 

 After their first stages are past tliey are as follows (Plate Four, fig. 8): 

 The head is mostly sooty black, this color being nnich liroken up by irregular 

 light yellow markings, and has a long triangular stripe down the middle of 

 the face and two converging curved lines on the top that are cream-colored 

 and conspicuous. Its surface liears many yellow hairs. The under side of the 

 body is mostly yellowish. The iiack and sides are rather dark lirownish gray, 

 with a light line along the middle of the back. There are eleven prominent 

 tubercles in a row along each side of the back, the first five being blue and 

 the last six red. These bear slender l)lack spines and a few short pale yel- 

 low hairs. Tubercles on the sides have more and longer hair most of which 

 is pale yellowish. Two small bright red tubercles without hair or spines, 

 some distance apart on the mid-line of the back toward the hind end, and a 

 conspicuous dark hairy tubercle on each side just behind the head are dis- 

 tinctive. The female worms often get to Ije two inches long, but the males 

 seldom much exceed an inch. 



The caterpillars spin much silk in their first stages and commonly drop 

 and hang liy a thread when disturbed. They do not do this when they get 

 larger, but they spin a few threads for support Ijefore pupating and often 

 make a scant cocoon. 



