574 THE AMERICAN NATURALIST. [VoL. XXXVI. 
In all species examined both simple hairs and glandular 
hairs were found to be supplied with a bipolar sensory nerve 
cell and fiber. Sometimes, as in Pieris and Datana, there are 
two quite distinct kinds of hairs, large 
and small. In this case the large hairs 
are supplied by large bipolar nerve 
cells, and the small hairs by small 
ones (Fig. 20). 
In tiger moths and tussock moths 
the hairs differ somewhat from those 
in other forms; here the single hairs 
Fic. 14. — Section of hair from body of other lepidopterous larvae are repre- 
e sented by bunches of hairs clustered 
together on tubercles. Each tubercle is supplied by one 
or more large nerve trunks, which break up on entering the 
tubercle. A bipolar nerve cell from each 
hair in this case is harder to determine 
absolutely ; but as some of the hairs were 
found to have such nervation, probably all 
do, for all are of the same kind. The 
structure of these hairs differs somewhat 
from those already described in the form 
and shape of the cells, these sometimes F 
being hollow or saclike with radiating 
nuclei (Fig. 2). The base of the hairs also presents variations, 
as shown in Fig. 2; here the chitinous base of the hair seems 
to extend down below the level of the cuticle. In a section 
through the base of a hair of Notolophus 
(Fig. 21) the opening of the hair is seen 
to be nearly closed in two places by strong 
processes of chitin, and sections taken 
just one side of the middle line show 
apparently a closed hair, indicating how 
small the opening is in the base of the 
hair. 
All the hairs examined in lepidopterous larvae were open 
and undoubtedly sensory, that is, supplied with bipolar 
sense cells. 


Section of hair of 
IG. 15. — Se 
Basilarchia archippus. 

Fic. 16. — Hair from Samia 
cecropia. 

