22 NEW YORK STATE MUSEUM 



and eating away the tissues of the infolding under side. The in- 

 jured portion turns dry and the retreat contains numerous small, 

 black particles of frass. The young larvae are probably miners in 

 the leaf. The whitish, silken cocoons in which the final transfor- 

 mations occur, are frequently made on the leaves close to the affected 

 area, though an occasional cocoon is spun under the partly rolled 

 leaf tip. Moths were reared March 25, 1912 and, judging from 

 reports received from various persons, it is probable that breeding 

 may be more or less continuous under the usual greenhouse con- 

 ditions. 



Description. The parent insect is a delicate moth with a wing 

 spread of only about three-eighths of an inch. The forewings are 

 yellowish, with large, purplish areas and a series of purplish dots 

 along the costal margin of the broad, yellowish portion. The hind 

 wings are slender, light pearly gray and long-fringed. This species, 

 according to Mr Busck, is allied to G. v i o 1 a c e 1 1 a Clem. 



Larva. Length, one- fourth of an inch. Head unusually large, 

 depressed, yellowish, the mouth parts well developed and the eyes 

 apparently represented by a large, circular, brown spot. Thoracic 

 legs well developed. Thorax yellowish and with the region just 

 above each leg marked by several distinct swellings. Abdomen 

 apodal, yellowish, and with a distinct though irregular fuscous 

 band on the penultimate segment. 



Cocoon. This is nearly one-fourth of an inch long, about three- 

 thirty-seconds of an inch in diameter and faintly suggests the 

 familiar Bucculatrix cocoon, though there are no distinct longi- 

 tudinal ribs. It is a well-defined, thin, silken structure usually 

 lying longitudinally on the under side of the leaf and frequently 

 ■covering more or less of the mined area. 



Remedial measures. Treatment with tobacco preparations, 

 either by fumigation or spraying, appears to be a very effective 

 method of controlling this insect, since practically no caterpillars 

 were to be found in greenhouses after such treatment. It is not 

 known whether spraying or fumigation gave the best results. 



ARBOR VITAE LEAF MINER 



Argyresthia thuiella Packard 



The small caterpillar of the arbor vitae leaf miner limits its 

 operations largely to mining the terminal sprays of arbor vitae 

 foliage and causing the latter to turn brown. There is, as a rule, 



