3 - Norsk entomologisk forening

170 Andreas Strand
Ptilium m um n. sp. Elongate, very small, narrow and slen-
der, somewhat flattened, rather shining, very finely sculptured,
clothed with greyish pubescense, fuscous with apex of elytra
lighter, antennae and legs yellow. Head slightly narrower than
thorax, eyw large, prominent, antennae with club slightly thick-
ened, thorax with a transverse depression, sides rounded in front
and contracted behind, broadest a little before middle with a strong
central channel and a very indistinct depression on each side,
diverging in front, elytra not much broader than thorax, rather
parallel-sided, tibiae strongly dilated at apex.
L.: 0.475 nun.
Of this extremely minute and slender species, which is hardly
visible with the naked eye, I have taken a specimen from hen's
droppings at AK11: Brmnnrya, not. far from Oslo, on the 19th
June 1944.
Acrotrichis nana n. sp. Elongate, rather convex, head some-
what shining, antennae pitchy, thorax sh'ort, transverse an'd
slightly dilated, with sparse and rather obsolete tubercles, intier-
spaces reticulate, somewhat shining, posterior angles depressed
and slightly produced, elytra moderately asperate.
9: Spermatheca as shown in fig. 3.
L.: 0.6 mm.
One specimen from hen's droppings in company with Ptilium
nanum A. Strand at AK11: Brnrnn~ya, not far from Oslo, on the
19th June 1944.
This minute species is of the same size as Chevrolati, but
is easily distingqished being darker, less shining, less para'llel and
less depressed, the sides of the thorax are somewhat more dilated,
its posterior angles less produced and distinctly depressed, the
elytra are more asperate and less shining.
As is well known there is much confusion in this difficult
group, and it might seem rather daring to describe a new species
on a single specimen. As it seems to be impossible to clear up
the many doubtful cases, I am of the opinion that the nomen-
clature should be worked out on the basis of an examination of
the genitalia, particularly of the females. A start has been made
by Rosskothen (Zur Kenntnis der deutschen Acrotrichis-Arten.
En8. Bl., 30, 1934, p. 113) and Renkonen (Uber die finnischen
Arten der Gattung Acrotrichis Motrsch. -- Ann. Entom. Fenn., 5,
1939, p. 177).
The spermatheca of Chevrolati is unknown to me, but as will
be seen from the description of the new species, there is no pos-
sibilitly for mixing up these two species.