HETEROSAIS. 61 
on its lower side. Lower discocellular of secondaries of female strongly curved and bent 
to a large acute angle, where a recurrent nervule is emitted; lower radial strong; 
middle discocellular meets the subcostal at a right angle, the upper discocellular and 
upper radial being absent. (Type Jihomia nephele, Bates.) 
The neuration of the secondaries of the male of insects of this section is quite peculiar, 
and in this respect represents the simplest type of wing-structure to be found in the sub- 
family Danaine, though Pteronymia is of almost as simple a construction in a different 
way. Taking this fact as affecting the position of Heterosais in the subfamily, it should 
perhaps stand at the head of the Rhopalocera; but, on the other hand, the presence in 
the female of a front leg with a five-jointed tarsus is opposed to this view. ‘This is 
a point best reserved for a general review of the whole of the Danaine, being rather 
beyond the scope of a faunistic work like the present. | 
1. Heterosais nephele. 
Ithomia nephele, Bates, Trans. Linn. Soc. xxiii. p. 548°; P.Z.S. 1863, p. 244”. 
Hymenitis nephele, Butl. & Druce, P. Z.S. 1874, p. 333°. 
Alis fuliginoso-hyalinis, venis nigris divisis et fusco-nigro circumcinctis, macula subquadrata obliqua eodem 
colore ad cellule finem vittaque cretaceo-alba ultra eam a costa ad marginem externum extensa, et macula 
submarginali in angulo anali albescente: subtus ut supra, sed coloribus opacis rufo tinctis. 
Hab. Costa Rica (Van Patten*, Carmiol); Panama, Chiriqui, Santa Fé (Arcé), Lion 
Hill (M‘Leannan ?).—Ecuapor ; Upper AMAzoNs'. 
Heterosais nephele was first described by Mr. Bates from specimens obtained 
during his expedition on the Amazons at Tabatinga, near the frontier of Brazil and 
Peru. It has since been found in some numbers by collectors in Ecuador, in the valley 
of the Rio Napo and other localities on the eastern slopes of the Andes. Absent from 
Colombia, the species reappears in Central America, where it is found throughout the 
State of Panama and in Costa Rica, being especially abundant on the line of the Panama 
railway. 
Specimens from Central-American localities are very constant in their characters, and 
show the peculiar nerve-structure of the secondary wings, which distinguishes this and 
its allies from other forms of this group of insects. 
2. Heterosais cadra. (Ithomia cadra, Tab. II. fig. 5.) 
Ithomia cadra, Godm. & Salv. Ann. & Mag. N. H. ser. 5, ii. p. 259. 
H. nephele similis, sed margine anticarum interno rufescente et area posticarum interna (venis inclusis) rufescenti 
induta differt. 
Hab. Panama, Rio Gatun (£i6de). 
This is a close ally of H. nephele, differing in the points indicated above. Two speci- 
