1886.] Entomology. 813 
fuller development than C. fraxini in bearing the characters upon 
such segment. The processes vary considerably in grade of de- 
velopment amongst the segments, and he said he had not yet 
been able to make out their precise order, but he submitted a 
somewhat rough sketch of the appearance of the abdominal seg- 
ments of C. a/acta as shown by a two-inch objective. The first 
drawing exhibited the internal structure of the dissected portion 
before the fatty tissues were removed; but little of the processes 
could be made out from that point of view, and they were more 
clearly to be seen from the other aspect; also a side view show- 
ing the contour of the natural size. The large view of four of the 
Spots presents an idea of the diversity of form in the individual 
animal, and the two additional sketches show the processes dia- 
grammatically. Mr. White said that the only conclusion he 
could arrive at respecting them was that they were functional 
organs of a special nature, and he observed that he should be 
very glad if any one present could suggest an explanation of any 
such function, or throw some light upon the question of their 
o 
portions of the caterpillar had been squeezed out, these organs 
pose. 
‘i reply to some observations from Professor Meldola, Mr. 
White said he had not found any similar organs in any other 
species, though he had looked well for them; and in reply to 
Mr. J. Jenner Weir, who suggested that they might act as 
sucker: S, he stated that the objection to that explanation was that 
the skin covering them was perfectly tight. There were in some 
instances pairs of minute holes which might communicate with 
a atmosphere, and probably did, but otherwise air was closed 
rom them. There appeared to be a motile closing of the ar- 
rangement of tentacles like the clasping together of fingers, but 
this could not apply to the open continuation of the serrated 
edge of tentacles above this seam of the lip, which is not unlike 
the labellum of some orchid. 
THE DARKENING OF THE HAIRS OF THE LARVA OF ACRONYCTA 
BEFORE Pupation.—During the past summer (1885), I noticed 
that the long white hairs of this larva become dark, as we i 
f y, before pupation, when the organism is wandering about to 
nd a place in which to burrow. I then remembered that I had 
o 
Plentifully upon birch and alder in the near forest. As the larva 
p lization of the incidental changes of color before pupation. 
Feviously, during larval, life, the organism rests motionless in a 
Swed position on the under side of the leaf, and the body is 
almost completely hidden by the long white hairs, and the effect 
