120 Annals Entomological Society of America  [Vol. VII, 
The Lasiocampide, like the Sphingide, show a tendency 
to increase of muscles, but it is slight. The deeper transverse 
fibres alone become numerous and unstable; they are weak 
and altogether much as one would expect in a form which had 
passed through a lappet-bearing stage and was degenerating. 
It is not unlikely that such a larva as Epicnaptera will show 
a strong and highly specialized lateral system. The differences 
between the two species is slight, in the first segment disstria 
has only three, americana usually five ventral rectus muscles; 
the lappets are much distincter in disstria, but not really 
functional, so that the difference is not noticeably reflected in 
the muscles. As a whole the genus is characterized by the 
massive upper fibre of ¢, a suggestive character in a lappet- 
bearing family, and the frequent presence of the aberrant 
fibre f’ (as figured) in both species. In the eighth segment 
there is a large tracheal tuft, which may serve as a sort of 
lung to aerate the blood where it first enters the heart. 
The Noctuide are marked by their simple and normal 
condition, without the primitive points of Cossus or the special- 
izations of the others, and are closely similar to each other. 
p and x meet on the middle line, but do not cross, as in Cossus. 
In general they are much like Cossus, but possess 4, and p’. 
The tracheze are reduced and inconspicuous. Of the two 
species the Noctua had slenderer lighter muscles. The insertion 
of p along the midventral line is a little different in character, 
and as it leaves its trace on the skin may prove a help in identi- 
fying in this difficult group. 
A Catocaline caterpillar, apparently a Pheocyma, shows 
a number of interesting specializations, apparently connected 
with its extraordinary jumping power. The thorax (Plates 
XVII and XVIII) is normal in general plan, but with various 
oblique muscles joined end for end into long sets; four pair of 
these, namely, EK, a;, a, and o,; C*, L-and Ge, @.s and Wend 
c, f and C extend the whole length of the thorax and there are 
several other shorter sets, while only the a system of the 
meso- and metathorax was recognized by Lyonet in Cossus. 
The peculiar breaking up of S in the metathorax at least, 
caused apparently by the attachment of I through it, does 
not even occur in other Noctuids, about the mesothorax I am 
uncertain, as that part of my specimen was damaged in dis- 
section. The principal peculiarities of the abdomen, aside 
