196 ' MR. H. W. BATES ON THE LEPIDOPTERA 
structure of the anterior legs in the adult state of the insects. The Heterocera have 
always six perfect legs : most of the families of Rhopalocera have the anterior pair in a 
more or less rudimentary condition ; and as the atrophy seems to have reached its furthest 
stage in the Heliconidce, this group must he considered as occupying the highest rank in 
the order. Other characters accompany the one derived from the structure of the legs, 
which it is unnecessary here to enumerate. It will he seen from these remarks that the 
order Lepidoptera is one of those groups in the Animal Kingdom which show, heyond the 
many collateral branches of development that always exist, a clear linear advancement 
of organization. 
The Heliconidce, Danaidce, and Acrceidce are related to each other in a different way 
from that which appears in the received classifications. A few remarks on their mutual 
affinities are necessary, in order to exhibit the true relations of the Heliconidce to the 
allied groups of the Old World tropics. It has escaped the notice of all authors, that the 
Heliconidce are composed of two groups, which differ very considerably in important 
points of structure ; in fact, the majority of the genera of which the family is composed 
ought to be withdrawn from it, and placed with the Danaidce. The very great superficial 
resemblance between the two sets of genera has led to their being united by all authors, 
and prevented inquiry into their real relationship. To avoid innovation, I will retain the 
family as it stands, and call the group which is allied to the Danaidce, Danaoid Heli- 
conid^:, and the other, which approximates somewhat to the Acrceidce, Acr^eoid Heli- 
conid^:. The Acrseoid group comprehends the genera Heliconius and Mieides; the 
Danaoid, the whole of the remaining Heliconidce. The following are the distinguishing 
characters of the two groups : — 
Acrceoid Heliconidce. The hind wing-cell is very small, and the nervures are so 
arranged that the upper and lower radials * (discoidal nervures of Doubleday) appear 
to be branch and sub-branch of the subcostal nervure, the discocellulars being short 
and continuous with them ; the costal nervure is prolonged to the apex of the wing. 
The larvae are similar to those of Acrcea and Argynnis {Nymphalidce) , being beset 
with hispid spines \. The head is broad, the palpi thick. 
Danaoid Heliconidce. The hind wing-cell is very large, and irregular in shape ; the two 
radials never appear as branches of the subcostal, but are very uncertain in position, 
owing to the very vacillating length and direction of the discocellulars : the costal 
nervure is short, and terminates on the costa, not reaching the apex of the wing. 
The larvae (only one species is known) are smooth, like those of the Danaidce, but 
are furnished with tubercles, instead of long fleshy threads. Head small, orbicular ; 
palpi slender % . 
* I have adopted the terminology of Doubleday (Doubl., Hewits., and Westwood's Genera of Diurnal Lepidoptera) 
with regard to the neuration or veining of the wings, excepting that I call the " nerrules " of the subcostal and 
median nervures " branches," and the " discoidal nervures " « radials," these alterations appearing necessary to 
prevent the verbal confusion of nervule with nervure. and rUsomrlnl ™<-h ,« e ™™ii„ia,. 
t 
Heliconius Erato (and 
Mechanitis Polymnia. 
Lybia. We are acquainted, through other sources, with the larvae of H. Mefoomene. H 
X 
<c 
rip arum 
Wiener 
Specimen Faunae Lepidopte- 
