14 BULLETIN 1032, U. S. DEPARTMENT OF AGRICULTURE. 



often some larvae, after feeding in a cluster of berries, will spin their 

 cocoons and also pupate on the inside of one of them, or they may 

 fasten their cocoons between the berries, mixing their silk with frass 

 and any skeletonized leaves available. This is commonly true of the 

 larvae of the second generation. It is not very unusual, therefore, to 

 find some berries with the empty pupa cases protruding from a hole in 

 the side. The great majority of the larvae of all generations, how- 

 ever, descend to the ground to pupate. 



The Cocoon. 



As previously referred to, the cocoon of the blackhead fireworm is 

 composed of strands of silk which the larva fastens to any surround- 

 ing objects, as frass. leaves, or berries, and more or less loosely draws 



Fig. (J. — The blackhead flieworm : Typical cocoous formed out of dead eranherry leaves 

 beneath the vines. The ones in the top row have been opened to show the interior ; 

 those in the lower row show the empty pupa cases protruding. All slightly enlarged. 



about itself preparatory to pupation. The interior of the cocoon is 

 shown in jfigures 6. 7, and 8. It is in cocoons similar to these that the 

 larvae pass through a resting period followed by a final molting of 

 the larval skin. This resting and molting, during which the pupa or 

 chrysalis is formed, is called pupation. 



THE PUPA. 



The pupa or chrysalis of the fireworm is about 5,5 mm. or a little 

 less than one-fourth inch long by 1.5 mm. or about one-sixteenth inch 

 wide, and of a light amber j^ellow color immediately after casting the 

 larval skin. This color soon changes to a deeper amber brown, and 

 in pu|)8e about to change to adults the color is a very deep amber 

 approaching almost black. The pupae are not usually encountered 

 without a rather close examination of the leaves and trash beneath 



