WALNUT HUSK-MAGGOT. 6 
and Banks, 5 in 1912, reared flies from butternuts at Plummers Island, 
Md. There are specimens in the United States National Museum 
from West Willow and Allegheny, Pa., and Dr. J. M. Aldrich, of 
the Museum, has in his personal collection specimens from Blue 
Ridge Summit, Pa., and La Fayette, Ind. During the present in- 
vestigation the writer has collected or otherwise obtained specimens 
from the following localities: Boston, Mass.; Wallingford, Conn.; 
Lockport, N. Y. ; West Willow and Washington Heights, Pa. ; Co- 
lumbus, Ohio ; New Windsor, Md. ; Washington, D. C. ; and French 
Creek and other localities in West Virginia. 
FOOD PLANTS. 
The walnut husk-maggot has been known to attack commonly the 
husks of the black walnut (Juglans nigra) and the butternut (-7. 
cinerea) . The writer has reared adults from the husks of the Persian 
walnut (J. regia) and Japanese walnut (/. sieboldiana). Of the 
foregoing hosts the black walnut and Persian walnut are preferred 
to the others, probably on account of the thicker husks. 
DESCRIPTION OF LIFE STAGES. 
THE EGG. 
The egg (PI. II, &', c, d) is white, banana-shaped, distinctly curved, 
0.9 to 1 mm. in length by 0.2 mm. in width, one end tapering gradu- 
ally to a rounded point, the other end tapering more abruptly and 
ending in a minute but distinct spur or pedicle. The eggs are placed 
in masses compressed closely together (PI. II, £>, c, d) in oviposition 
punctures extending 2 mm., more or less, beneath the skin of the 
nuts. The female will oviposit freely in any fresh puncture which 
she may find in the skin made otherwise than with her ovipositor. 
Small punctures made experimentally in the husk with a sharp point 
usually were found promptly by the females and filled with eggs. 
In some cases such punctures would be packed with eggs and the 
flies would continue to oviposit on the surface until a small mound 
of eggs covered the opening in the skin (PL II, d). One artificial 
puncture in a black walnut was found to contain 186 eggs and several 
punctures made with the ovipositor were found to hold upwards of 
GO eggs each. The eggs apparently hatch in from 7 to 10 days. 
Oviposition takes place only in the green part of the husk, but 
after the maggots hatch and begin to feed the point of attack soon 
shows as a black spot on the surface (PI. IV, a). This spot increases 
rapidly in size as the burrows of the maggots penetrate the tissues 
5 Banks, Nathan, the stbuctube of certain dipterous lary.ts with particular ref- 
erence to those in human foods. U. S. Dept. Agr., Bur. Ent., Tech. Ser. Bui. 22, 
p. 32. 1912. 
