484 Baron Osten Sacken on the differences between 
a species to which the author has given the provisional 
name of Maruina Ursula. When we compare it with 
Prof. MialFs figure (Tab. iii., fig. 1) of the larva of P. 
canescens, and read the description (pp. 142-144) the 
resemblance between the two larvae becomes apparent. 
About P. canescens we read : " The head is rather small 
and completely exserted. On its upper surface the tri- 
angular clypeus, pointed behind, occupies a central 
position ; it is flanked by the two epicranial plates. . . . 
On the sides of the head, behind the antennge, are the 
eye- spots, which are oval, convex, pigmented.^' These 
passages concerning P. canescens are equally applicable 
both to the head of Dr. Miiller's larva (Tab. x., fig. 1), 
as to the detail-head of fig. 3 (of Maruina pilosella). On 
the anterior dorsal part of the thorax we perceive, in 
MialFs Tab. iii., fig. 1 (P. canescens) as well as in Dr. 
Muller*s Tab. x., fig 1 (M. ursula), contiguous triangular 
chitinous plates, with a narrow interval between them ; 
the structural analogy is evident, although the difierences 
are easily perceptible. 
The other thoracic segments of the larva of P. 
canescens are described and figured as consisting each of 
two annuli, separated by transverse constrictions, each 
annulus bearing a narrow, transversely set dorsal shield. 
Two such transverse shields are visible on the thorax of 
the South American larva (fig. 1, M. ursula) behind the 
above-mentioned triangular plates. The abdominal seg- 
ments (P. canescens) are subdivided into three annuli 
(except the first, which has only two), and each of these 
annuli bears a transverse chitinous shield, like those of 
the thorax (Tab. iv., fig. 4). The abdominal segments of 
the three South American larvae are described very 
nearly in the same terms by Dr. Miiller : " The three 
species show three dorsal shields on each of the dorsal 
segments of the abdomen, and, laterally, these segments 
are very distinctly divided into three lobes (compare 
Tab. x., fig. 4, the fifth abdominal segment of 
jpilosella from above). The skin of the larva of P. 
canescens is described (p. 142) as : " Covered with 
chitinous tubercles, for the most part very minute. 
These appear nnder the microscope like nails, imbedded 
in the flexible skin. They take various shapes,^' etc. 
The dotted surface of the skin of the larva of M. ursula 
(fig. 1) may represent a similar structure, although it is 
