INSECTS, FUNGI, PLANT DISEASES, ETC. 



129 



Grape Leaf Folder (Desmia maculalis, Westw.)- — 

 " One of the noticeable features of a vineyard, particu- 

 larly in midsummer and later, is the many folded leaves, 

 the interiors of which have been skeletonized. This is 

 especially evident with thick-leaved varieties, the 

 whitish under surface contrasting strongly will) the thick 

 green of the upper. If the leaf be unfolded, it will be 

 found to contain a very 



active, w r i g g 1 i n g, 

 greenish larva, a little 

 less than an inch long, 

 which is apt to spring- 

 out of the fold and fall, 

 or hang by a thread. 

 The leaf itself will be 

 found to be attached 

 to the folded part by 

 means of numerous lit- 

 tle cords of silk. If the 

 larva is full grown, the 

 interior of the leaf will 

 be thoroughly skele- 

 tonized and soiled 

 with accumulated ex- 

 crements. The fold al- 

 most invariably brings the upper sides of the leaf to- 

 gether, the larva feeding, therefore, on what would be 

 the upper surface of the leaf. The larva transforms to a 

 reddish-brown chrysalis usually within a much smaller 

 fold of the edge of the leaf, but sometimes within the 

 larger larval fold. The moth, which, during the summer, 

 issues in a few days, expands about an inch, and is a 

 shining opalescent black, with wings bordered with white 

 and marked with white spots, as in the illustration, a 



Fig. 32 — Desmia maculalis. a, Male moth. 

 I>, Female, c, Larva, d, Head and tho- 

 racic segments of same, enlarged. 

 e, Pupa. /, Tip of pupa, enlarged. 

 g, Grape leaf folded by larva. Mar- 

 latt, Div. Ent. TJ. S. Dept. Agri. Year 

 Book, 1895. 



