472 iIPASWe Chancenie 
LEPIDOPTERA? \ 
Arzama obliqua Walk. 
Arzama obliqua Waik., a moth of the family Noctuidae, has been 
known in the adult stage for more than half a century. The species occurs 
throughout eastern United States and Canada, its host plant being Typha 
latifolia. In New York, near Ithaca, the writer has taken specimens 
from the following places: Michigan Hollow, Renwick Marsh, Bool’s 
Back Water, McLean Bogs, Cascadilla Creek, and Ringwood Hollow. 
Life history and habits 
The life history of this insect is unusual and interesting from an ecological 
point of view. There is only one generation a year. The full-grown 
larva passes the winter in its burrow in the plant. 
Eqg-laying.— The eggs are laid on the surface of one of the first-formed 
leaves of 7’. latifolia, from six to fifteen inches below the tip. This later 
becomes one of the outer leaves of the plant. The eggs are placed on 
the leaf several layers deep. The lower layer covers the largest area and 
contains from twenty-five to forty eggs, while the upper layers cover only 
the central part of this bottom layer, forming a gradually sloping mass 
and containing from ten to twenty eggs in the two or more upper layers. 
The total number of eggs in one egg mass varies from thirty-five to sixty. 
The whole egg mass is covered with a thick layer composed of a mixture 
of froth, hairs, and scales from the body of the female. The egg mass 
greatly resembles a mass of spider’s eggs (Plates XLI, 24 and 25, 
and XLVI, 65). It is of a dirty, yellowish-white color. It measures 
from twelve to fifteen millimeters in length, from seven to ten millimeters 
in width, and from three to four millimeters in height at the center. In 
shape it is oblong and convex, the edges gradually thinning out and 
adhering closely to the surface of the leaf. The long axis of the egg mass 
corresponds to the long axis of the leaf. 
One female apparently lays several egg masses. In dissecting out the 
ovary of one female, 225 eggs were found, all fully formed and developed; 
and since only thirty-five to sixty eggs occur in a single mass, this indicates 
that one female may deposit about half a dozen egg masses. ° 
3 The Lepidoptera mentioned in this paper have all been determined by Dr. W. T. M. Forbes, 
