REVIEWS. j 711 
Secondly, as to the relationship of the Trichoptera to the Lep- 
idoptera. It seems to us. that we each look upon this matter 
from a different standpoint. We would claim that the characters 
which Mr. McLachlan relies upon as allying the caddis flies to the 
moths are adaptive and of secondary importance. Let us leave 
them out of sight for the moment, and look at what the reviewer 
deems the more essential ones. Strip our examples of moths and 
caddis flies of their wings and legs up to the coxæ, removing the 
antennæ and palpi, and place the naked trunks side by side. We 
shall find a wonderful uniformity of structure in the head and body 
of the Lepidoptera, to which we have previously called attention. * 
We shall observe that the three portions of the lepidopterous 
head, the occiput, epicranium, and clypeus, always preserve much 
the same relation to each other. The front of the head is formed 
by the epicranium and clypeus, the latter usually being the larger 
of the two parts, though in the Tineids the two pieces are of 
nearly the same size. Looking at the thorax, another essential 
character of the Lepidoptera is the very short metathorax, and 
the absence of the præscutum. In one moth, the degraded Hepia- 
lus, the metathorax is much longer than in any other moth known 
to us, and the præscutum is well developed, resembling the “trae? 
Neuroptera in this respect. The head of the Phryganeidæ, though 
varying greatly in the different genera, differs invariably from that 
of the moths in the front of the head consisting of the clypeus 
alone enclosed in the broad orbits, while the broad vertex consists 
of the epicranium, which is-as large as the entire front of the head ; 
the head is wider and the eyes much smaller than in the moths ; 
and another important character is the broad, deeply excavated 
front edge of the clypeus, this part in the moths being invariably 
narrower and much rounded. { 
The metathorax of the caddis flies is always much longer than 
in the moths, often twice as long, and the prescutum is nearly 
always well developed. These characters of the head and thorax 
* Notes on the family Zygænidæ. Proc. Essex Institute. IV. 1864. p- 14. oe 
or further remarks and figures in illustration see our remarks On Synthetic 
Boston Society of Natural History. viii. 1863. 
Hallesus sp, Limnophilus des- 
pectus, Philopotamus sp., and Setodes exquisita. mi an ps me ve we ass 
tions of the body in these and other genera we eral ingoio whe er - a 
ave not overlooked the source of most 
most in use, such as the ti d sy 
cies. 
phara 
1 varying in different sexes of the same spe- 
