480 . P. W: CLAASSEN . 
_ Although the larvae had evidently just started their work, and more 
larvae continued to appear during the following days, no eggs could 
be found on the plants. Again, in Ithaca, on May 20, 1918, first-instar 
larvae were discovered at work in the tips of the leaves, but no trace of 
the eggs could be discovered. This suggests the possibility that the 
females deposit their eggs in the fall on some of the old plants or other 
objects in the field, and that the species overwinters in the egg stage. 
The larva— The larvae enter the leaf of the cat-tail near the tip and 
at once begin to work as leaf miners. In their mining they do not restrict 
their work to the longitudinal channels, as do the larvae of Arzama obliqua, 
but they zigzag back and forth in the leaf, cutting through both the 
longitudinal and the transverse ‘partitions. They feed on the chlorophyll 
and on the spongy parenchyma of the plant. The larvae are strictly 
solitary in their habits; only occasionally do two, or sometimes three, 
larvae occur in the same mine or even in the same leaf. The charac- 
teristic mine produced by the larva is shown in Plate XLII, 37. It is 
easily distinguished from the mine made by Arzama obliqua. 
When the larvae are ready for the first molt, they suddenly widen 
their mine to the outer margins of the leaf, thus producing a narrow 
transverse mine extending nearly the entire width of the leaf but not 
severing it completely. This causes the leaf to wither from this point 
outward to the tip. In this withered part of the leaf the larvae molt, 
after which they mine downward through the lower, uninjured part. It 
seems that the natural condition of the leaf, which is very moist, is 
unfavorable to the molting of these larvae, and it is in order to overcome 
this excess of moisture that they sever the conducting tissues, thus causing 
the leaf to dry quickly. In this manner they obtain the required dryness 
in which to shed their first coat. This allows the larvae to remain under 
cover, where they are more protected than they would be in the open. 
The characteristic appearance of such a leaf and the cast skin of one 
larva in the severed part of the leaf, just above the transverse cut, aze 
shown in Plate XLII, 37. 
The larvae of this species do not cease mining after their first molt, and 
come out of the leaf, as do the larvae of Arzama obliqua, but continue a 
miners in the leaf for some time, often remaining in the leaf through th 
second, and even through part of the third, instar. Then, however, th 
larvae crawl away from the upper part of the leaf and seek protectio 
