TypHa Insects: THEIR EcoLoGicaAL RELATIONSHIPS 507 
the point where the tender new tissue is forming. The effect of their 
work on the plant is very similar: the central leaves of the leaf bundle 
die and the plant fails to produce a fruiting stalk. 
_ C. pertinax, the weevil, begins its larval life as a stem borer, later 
becoming a borer in the rhizome of the plant. The eggs of C. pertinax 
are inserted into the sheaths of the plant, near the ground. The newly 
hatched larvae bore to the center of the stalk and hollow it out just above 
the crown, thus arresting the further growth of the plant. After feeding 
on the tender tissue at the center of the stem for some time, the larvae 
enter the rhizome and there feed on the more substantial starchy food. 
When full-grown, the larvae return to the stalk and there form a pupal 
chamber in which the transformation takes place. There is only one 
generation. The larvae are ordinarily solitary borers, although as many 
as seven larvae have been found in one plant. 
INSECT INHABITANTS OF THE RHIZOME OF TYPHA 
The inhabitants of the rhizome are the Coleoptera, Calendra pertinax 
Oliv. and probably Notaris puncticollis Lec. The larvae of C. pertinax 
feed during the major part of their larval period on the starchy core in 
the rhizome of the plant. By first tunneling out the center of the stalk 
at the crown of the plant, they prevent the formation of new leaves, and 
in this way the larvae cause the starch to remain in the rhizome for their 
nutriment which would otherwise be used up in the growth of the plant. 
The leaves already formed are left undistrubed to manufacture and send 
down more starch to the rhizome. Very likely the habits of N. pwnctzcollis 
are similar to those of C. pertinaz. 
