82 NEUROPTERA. 
for from the present material a complete series from H. bipartita-type to beyond 
H. titia-type, with all intergrades, can be made from one and the same locality, as 
Teleman in Vera Paz, or Southern Texas, or Nuevo Laredo (Tamaulipas). Nor is the 
variation seasonal, for the whole series from Nuevo Laredo was collected in the same 
month, July. 
The presence of a number of teneral individuals in the present series shows that, of 
the two colours on the wings, the brown first appears (see Tab. III.) and subsequently 
the red is indicated by a pale pink ‘“‘ wash” over the brown at the base of the front 
wings. This pink becomes a deeper and deeper red, while the brown is, at the same 
time, darkening. It is needless to say that a teneral male showing the markings 
of H. bipartita-type never possesses the markings of H. titia-type, but remains a 
H. bipartita-type until death. . 
Structurally, H. titéa, 3, is so closely related to H. tricolor, 3, that it is impossible 
to distinguish the one from the other in this respect. The greater extent of brown on 
the wings of the most darkly coloured WH. titia is not correlated with any greater 
density of reticulation, The males of the two species differ in the following colour 
peculiarities :—(1) In H. tricolor the area occupied by yellow on the metapleura is 
greater than that occupied by black ; the reverse is true for 1. titia. (2) The brown 
on the base of the hind wing of ZH. tricolor never reaches the nodus, extending in the 
most extreme case to 4%; of the distance from base to nodus and in most individuals to 
5 or less ; in H. titra the brown always reaches to the nodus and usually beyond it. 
(3) When the colours of the wings have matured, the basal red of the front pair is 
bordered externally with brown in H. ¢itia, but not in H. tricolor. . 
Seeing the relatively wide range of variation which exists in connecting H. bipartita 
with H. titia, it is remarkable that nothing in the present material bridges the much 
narrower gap between H. bipartita and #. tricolor, since a considerable range of 
territory is inhabited in common. It will not be surprising therefore to discover that 
H. tricolor is but the other extreme of the series in which HZ. bipartita and H. titia 
are terms. 
2. It is with much doubt and hesitation that I have separated the females of 
H. titia from those of H. macropus and its varieties, as shown in the preceding key. The 
old females of H. titia are readily distinguishable, owing to the dark brown colouring 
of their wings, but with the young females the case is quite different, as the wings are 
pale yellowish only, as they appear to remain throughout life in H. macropus. Indeed, 
I would have referred all the females which, by the preceding key, fall under “ young 
H. titia” to H. macropus, were it not that one of them is labelled as having been taken 
in coitu with an undoubted H. titia male. I shall not be surprised, therefore, if some 
future investigator finds that I have erred in differentiating the females of these two 
species. After repeated efforts, I, however, have not been able to do better than is 
