504 P. W. CLAASSEN 
Both of these insects are well adapted to live in the heads of cat-tail. 
Both spin an abundance of silk whereby they tie the pappus together 
and keep the head from being torn and the seeds from being scattered. 
This process of tying the pappus together assures the larvae of retaining 
their food supply and also furnishes them a protected and sheltered place 
for passing the winter. D. julianalis, however, being a less hardy southern 
form, was unable to stand the severe temperature during the winter 
of 1917-18, and all the larvae found in the Typha heads that spring 
were dead. 
Archips obsoletana should probably be classified as an incidental feeder 
on cat-tail. It is a typical leaf-roller, occurring chiefly on strawberry 
plants. However, once the larvae locate on the head of the cat-tail, 
they spend the entire larval period there and transform to the pupal 
stage on the plant. Since there are three generations a year, it is very 
probable that never more than one generation is passed on cat-tail; for 
these insects feed only on the tender styles of the pistillate flowers, and 
as these soon dry up, the later generations would not be able to find the 
tender food they relish. When living on the strawberry plant, these 
larvae roll themselves up in a leaf for protection. On the head of eat-tails 
they protect themselves by tying the stigmas together underneath with 
a lining of silk, thus forming a cover under which they live while feeding 
on the styles of the flowers. When placed in a cage with cat-tail leaves, 
the larvae prepare a covering for themselves by tying two leaves together 
and crawling between them. At the time of pupation they tie a leaf to 
the head of the plant and thus obtain the protection necessary during 
their transformation. 
In the spring, the females of Ischnorrhynchus resedae deposit their eggs 
in the old, downy heads of the cat-tail. The eggs closely resemble the 
seeds of cat-tail and thus are well protected from enemies. Immediately 
after hatching, the nymphs begin to feed on the seeds of the plant. They 
thrust their beaks into the dry seeds and apparently obtain their nourish- 
ment by injecting saliva into the seeds, which dissolves the solid material 
there so that they can suck it up into the body. The entire nymphal 
stage is spent in feeding on the dry seeds, a very remarkable and interesting 
adaptation. Due to the work of L. phragmitella.and D. julianalis, the 
seeds of many of the old heads are kept from being scattered by the winter 
storms, and Ischnorrhynchus resedae siniply takes advantage of these 
