BUTTERFLIES OF MAINE. 7 
division of the insect into head, thorax and abdomen, much 
more plainly than the larva. The parts of the covering take 
special names according to their uses; as the head-case, eye- 
cases, tongue-case, leg-cases, antenne-cases, trunk-case, 
wing-cases and the abdomen-case which consists of nine more 
or less distinctly separated segments with the future spiracles 
along the side, and the anal orifice indicated on the last 
segment. The apex of the last segment is called the cremas- 
ter which varies greatly in form in the different species, but 
is always armed with hooks or spines by means of which the 
pupa secures itself to the threads of silk spun for that pur- 
pose. 
Some pup have spines along the abdomen or on other 
parts of the body, and there are other angles and protuber- 
ances, as two in front, which are the palpi-cases, several 
along the edges of the wing-cases, and in some species, there 
is a process upon the top of the thorax in the form of a long 
thin pyramid or resembling a man’s nose. The majority of 
butterfly pupz have a greenish, or yellowish grey, or brown 
color, and some have metallic spots on them. 
EXTERNAL ANATOMY OF THE IMAGO. 
The term imago is applied to the insect as soon as it emerges 
from the pupa case. It has three principal divisions; head, 
thorax and abdomen. The head is more or less globose in 
form, and has on each side a globular or ovate compound eye. 
On the top of the head, between the eyes, are two long 
jointed antennz which have the outer end enlarged into what 
is called the club. In some species the club terminates quite 
abruptly, while in others (some of the Hesperide), it tapers 
more or less to a fine point and is curved or hooked. On 
the under side of the head are situated the mouth parts which 
consist of a pair of three-jointed palpi covered with hair-like 
scales, which curve up in front more or less closely against 
the head. Near the base of the palpi, and between them, 
is situated the proboscis or tongue; a long, tapering, horny 
