6 BULLETIN 554, U. S. DEPARTMENT OF AGRICULTURE. 



follow the nervules beyond the cell, while a supplementary brownish and 

 oblique line intervenes between the oblique portion of the costal stripe and 

 the inner margining of the inner silvery band ; the extreme outer margin of 

 the wing has a black line on the upper half, and on the lower half at the 

 nervule tips three or four black points ; the fringe is silvery. Hind-wings 

 uniform silvery gray, narrowly edged on the upper half of the outer border 

 with pale brown, the fringe silvery white. Expanse of fore wings, $ 15 mm ; 

 9 17 mm . Described from four bred males. 



The average length of 14 specimens, measuring from front of eye 

 to tip of wing when folded, is 9.4 mm., or about three-eighths of an 

 inch. The females are rounder of abdomen and average larger than 

 the males. 



THE COCOON. 



The cocoon is composed of scraps of debris found on the floor of 

 the bog, usually consisting of bits of dead leaves, bark, twigs, fine 

 roots, grasses, sand, and dried excrement of the larva, with now and 

 then a whole leaf attached loosely to the outside. This material is 

 held together by fine strands of white silk, and the interior has a 

 lining of white silk, parchmentlike in texture. In sandy locations 

 the external part of the cocoon is sometimes made entirely of sand. 

 However, for New Jersey bogs the typical cocoon is made of trash 

 and appears dark brown in color. 



The shape of the cocoon is variable (PI. VI, B.). In some in- 

 stances it might be described as resembling in miniature a short- 

 handled Indian club, while others appear of a curved cucumber 

 shape. One end is always broadly rounded, being of greatest diame- 

 ter about one-third the distance to the smaller end, and tapering 

 to a cylindrical, slightly curved neck. Some loose strands of silk 

 are placed in the neck for protection, but the end is not securely 

 sealed as are the walls. When pupation occurs the pupa lies with 

 head toward the neck, and the moth is able to push its way through, 

 leaving the pupal shell within the cocoon. One can not tell from 

 external appearances whether the moth has emerged, because the 

 exit hole is well concealed by the arrangement of pieces of trash 

 which tend to fall back into position after the passage of the moth. 

 The measurements of 13 cocoons are as follows : Length 11 to 18 mm., 

 average 13.84. ; greatest breadth 5.5 to 10 mm., average 6.88 mm. 



Vertical cylindrical cases often encountered on cranberr}^ bogs, 

 which might be confused in the mind of the grower with those of 

 the girdler, are those formed by larvae of caddiceflies — harmless in- 

 sects which breed in wet places. There are many styles of these 

 caddicefly cases (PI. VI, A), and they are often found projecting 

 straight up through the trash in areas infested by the cranberry 

 ffirdler. 



