34 
new aspen-feeding species, which he names sorhayeniclta, and, at the 
same time, he takes Zeller’s var. b. (the clouded form) as the type of 
the species mjfu&ella. Liiders appear to hold that the type of a species 
is the most abundant form. This may be so of the natural type, but 
it is usually considered that an author’s type is the form first described 
under the distinguishing specific name. 
The synonomy, therefore, would run :— 
Oposteya saliyna (pro parte), Zeller, 1839. 
Oposteya stiff usella, Zeller, 1847. 
Phyllocnhtia suff'usella, var. c., Zeller, 1848. 
Oposteya (Phyttocnites) tremulella (Fisch., M. S.), Heeger, 1852. 
One word about Fischer’s (or Herrich-Schaffer’s) Oposteya tremu- 
lella. The name, as far as appears to be known, is only found in the 
“ Schlesischer Tauschverein fiir Schmetterlinge ” (Benefit iv., p. 21, 
1843), but as the name alone is mentioned, without any description or 
reference, it must be taken, I suppose, as a nomen nudum. Should, 
however, a description turn up we may have to substitute tremulella 
for one of the other specific names—perhaps for sorhayeniella, the 
aspen-feeder. 
Ovum.— As the creature commences its own separate existence as 
soon as the egg is laid, that moment in its life-cycle may be taken as 
the starting point. 
The ovum, then, is deposited on the leaves of at least three species 
of poplar —Populus niyra, I J . pyramid alls, and P.bahamifera. 
The young, somewhat sticky, or viscid leaves are usually chosen. 
In some instances I have seen leaves selected which were so lately 
in the bud that the margins were still rolled. The greater proportion 
of the ova is laid on the upper surface of the leaf, but they may very 
frequently be found adhering to the lower surface. It may be that the 
moth finds it easier to place the egg while reposing on the surface than 
while clinging to the under surface. From a larval point of view, the 
upper surface may be preferable, on account of the, possibly, more suit¬ 
able cell formation, and on account of the ribs and veins being less 
prominent, and, therefore, more easily passed over in the course of 
mining. The under surface, however, perhaps, has the following ad¬ 
vantages :—The larva is better sheltered from either hot sun or cold 
rain, and less exposed to the attacks of its enemies. 
The situation most frequently selected is a point almost touching 
the mid-rib, and distant about one-third the length of the leaf from 
the apex. Sometimes the egg is placed close to a lateral vein, more 
rarely on the plain surface between two veins. I have never seen the 
egg on the extreme edge of the leaf, neither on the petiole nor on the 
bark of the twigs. The ovum is laid singly, though I have found two 
side by side, but not in contact. One egg on each surface of the leaf 
appears to be the best possible, though such large leaves as we some¬ 
times find on the balsam poplar can accommodate two larva' on each 
surface. On one occasion l found five eggs on one very small leaf of 
a Lombardy poplar, but even then they were all laid separately, not 
packed side by side like the ova of (iracilaria syrinyella, nor imbri¬ 
cated like those of 1 ponomeuta nymtipuuctatus, both of which species 
begin life by mining into the leaves of their respective foodplants. 
The ova of Phyllocnistis stiff usella, though minute, are really con¬ 
spicuous, especially when new, owing to the milk-white colour, which 
