Article beginning on page 219.
Psyche 9:219-221, 1900.

Full text (searchable PDF)
Durable link: http://psyche.entclub.org/9/9-219.html

The following unprocessed text is extracted from the PDF file, and is likely to be both incomplete and full of errors. Please consult the PDF file for the complete article.

Psyche, Vol. 9. Plate 2.
I--
.
.-I
-- -
--
THE GENUS NEELUS.




================================================================================

PSYCHE,.
REVIEW OF THE COLLEMBOLAN GENUS NEELUS AND DESCRIP- TION OF N, MINUTUS N. SP.
BY JUSTUS WATSON FOLSOM, CHAMPAIGN, ILL. The name Weelus murinns was given
by me* to a curious collembolan that
I found in a greenhouse in Cambridge,
Mass., under circumstances that in-
dicated Jamaica as its home. The
value of the generic characters which I
originally drew from a single species is now substantiated through two more
forms : " Me~alotliorax " minims, de-
scribed by Willcmf from specimens
obtained at the Hotanic Garden of
Ghent, Belgium, and Neehis minutus, a
Massachusetts species described below.
The genus Neelus can now be char-
acterized with more detail than it could before, thanks to the additional species. First in importance are the extraordinary development of the thorax, which greatly exceeds the abdomen in length, and the
unusual structure of the antennae, as
compared with Sn~inthurus and Papirius
-the only other Collembola of globular
form. The head is ovate, horizontal or
subhorizontal, and broadly articulated.
Eyes and postantennal organs are absent. The antennae are short-not more
than one half as long as the headÌÔ
and consist of four simple segments, the second and third of which are incrassate or subclavate. Body globular; pro-
thorax slightly reduced dorsally, meso-
thorax not reduced, mctathorax conspic-
uously long. Legs long and slender;
coxae (fig. I) especially long ; two pre- coxal segments are evident. Both claws
present. The ventral tube is about as
long as the antennae and emits a pair
of hemispherical papillae. Abdomen
swollen before the manubrium; anal
tubercle obsolete. Furcula twice as
long as the antennae ; manubrium stout,
distally bifid ; denies cylindrical in
lateral aspect ; mucrones elongate, serrate or entire. Appendages sparsely clothed
with short stiff setae; body almost
naked, except anally. Size minute.
Tracheae are apparently absent.
The stomach (fig. 2) differs from that
of every other collembolan genus in con- sisting of a longitudinal series of four spherical chambers, partially separated
by permanent transverse invaginatiom
of the wall; the intestine, also, becomes spherically, but temporarily, distended
by its contents. The food, vegetable
detritus, appears through the integu-
ment as four or five brown ovoid masses.



================================================================================

220 PSYCHE. [July, 190.
The first abdominal ganglion is the
last of the chain to be represented and
tends to unite with the ganglion of the
prcceding segment.
As all these generic characters appear,
not only in the two species of Neelus
found by me, but also in MegalotJiorax
7n//ii~nns Willem, the latter (and later) genus falls. A< mi72iiW/s, unlike the
oilier two species, has three pairs of
small cuLicular cupules, and the attitude or the head, as figured by Willem, is
more nearly vertical - an attitude, how- ever, that occurs at times in the other
funny ; finally, the segmentation of the body (obscure in m ~ i k s and &/atus)
is pronounced in minimus -- a difference also found , within the allied genus
Sminthurus. With this last genus. Nee-
lus should be compared, although it may
be stated at the outset that the differ- ences between the two are much greater
than those that separate Sminthurus
and Papirim.
As contrasted with S~nintl~ums, then,
the head of Neelus is articulated by its entire base, without a projecting vertex, higher than the neck. The antennae,
in particular, instead of being longer
than the head and slender, are but half
as long as the head and have stout seg-
ments, the last of which is not annulate, as it is frequently, although not always, in Sminthur~~s. The thorax, far from
being condensed, with the legs brought
together, is much more extensive than
the abdomen - an essential difference
-and the legs are well separated.
The metathorax is remarkably long and
the coxae as well.
Again, the ventral
tube is long, of peculiar form. and does not extrude long filamentous tubes.
There is no prominent anal tubcrclc in
Neelus. The stomach is divided into
spherical compartments, instead of being cylindrical as in Sininthusus. Other
differences, of minor importance, exist
but need no mention.
Neelus should, however, be assigned
to one family with Srnini-hurus and
Papirius, notwitl~standiug my earlier
opinion, and clearly becomes the most
primitive genus 01 S~ninthuridae. In
Willem's (lgoo, p. 67) words:
'' llTtyaivf/io~x [Neelns] est mi Sminthuri- de qni a conservi! les caiwtfei-es archaYques suivants :
I. hi forme cles aniennes;
2. le d6veloppement du thorax, don1 seul Ie premier anneiui a subi uric I$g&re rdgres- sion ;
3. la persistence tris nctte de la segiricntfi- tion abdoininale; [tl~is upptics TO species minimus only, at present.]
4. la nettetk des deux articles pr6coxiens des pattes;
j in simplick4 de I' nppareil reproclucteur male.
C'est done, sons bien dos rapports, Ie plus iu'cha'ique deb Sminthurides : il s'est s6parG de la souchc du groiipc avant Pros~ninihiirns [of Willem] et SminiJiurus.
I1 otfre comme fcp4cialisations secondah-es: a. la disparitiuii dcs ycux;
b. les Lrois cnpules sensorielles ; [applies Lo minimus only.]
c. In diminution de volume de I'abdomen, plus ramass.4 que chex Smi-i:fkwiis ;
d. 1' absence d' appnreil irach6cu ;
c. la structure spdciale de l'intestin moy- en."
The break between the Sminthuridae




================================================================================

July, 19011 PSYCHE. 221
and the cylindrical Collenibola is par-
tially bridged by Neclus, which, quite
unlike Sminthurus and Papirius, agrees
with the Poduridae in respect to the
form of the antennae, the articulation
and position of the head, and the form
of the papillae emittccl by the ventral
tube.
The three spccies of xcJus may be
separated as follows :
Segmentation pronounced ; superior claw
untoothed, with a basal pair o( subulate- processes (pseiulonj~chiae of Tullberg); dentes untoothed ; niucro sublinear, en- tire ; three pairs of culicular cupules
present, on mesothorax, metathorax and
fourth abdominal segments, respectively ; brown; maximum length, 0.25 mm.
minimis.
Segmentation obscure ; superior claw
nnidentate; denies toothed or spined;
mucro lanceolate in lateral aspect, and
serrate ; cupnles absent.
Superior claw with a basal pair of
linear processes (pseudonychiae) ; in-
ferior claw linear-lanceolate ; dentes
five-toothed ; ochraceous-buff ; max-
imum length, 0.7 mm. . mwims.
Superior claw not pseudonychiate ;
inferior claw lanceolate or oblong-
lanceolate ; dentes six-spined ; bluish
gray; maximum length 0.56 mm.
mtuutu4 n. sp.
Neelits nzinuf~~s I have found at only
one spot, an old pine forest in Arling-
ton, Mass., in rich black soil, perenni- ally clamp. The species easily escapes
ordinary observation on account of its
small size and dull color and I took
only about two dozen examples during
four years of continual search. One
specimen occurred under the loose bark
of a white oak log; the others were on
the under side of dead sticks or else in the soil. Minute white individuals,
scarcely discernible, appear early in July; full grown specimens occur in the mid-
dle of that month, are most numerous
in mid August and persist, in constantly decreasing numbers, even into Decem-
ber, long after the frosts have begun.
Areelus 't;~im;tus 11. sp. (Plate 2, figs, 3-11). -General color bluish gray. - the combined effect of bluish mottlings and a pale gruund color (fig. 3) ; sternum colored; appendages white, excepting a little color on the bases of the legs of large individuals; the amount of coloration increases with the size, young specimens being white. Head horizontal,
ovate. Eyes and postantennal organs absent, Antennae (fig". 4) Icss than half as long as the head ; ratio of segments, 2 : 3: 6: 5 ; sec- ond segment incrassate, simple or with a vcntral lobe; third incrassate; fourth conical. Body oval in dorsal aspect, with smooth con- tour, showing scarcelj a trace of segmenta- lion above. Thorax one and one half times as long as the abdomen. Claws small ; first mid second pairs of snpcrior claws (fi" 5) sliglitly curved, uniformly tapering, tii~ideii- tate; first pair of inferiors lanceolate, simple, one third as long us tlic opposed claws; sec- ond pair similar but a little longer; third pair of superior claws (lig. 6) broad basally, uni- dentate; third pair of inferiors oblong-lance- olate, simple, extending almost as far as the opposite claws; pseudonychiae absent. Ven- tral tube (figs. 3, 7, 8) subclavate with a pos- terior lobe near the base. Mannhrium (fig. 9) stout, slightly shorter than the dentes, hifid (fig. 10) ; dentes in lateral aspect (fig. 9) cylin- drical, in dorsal view (fig. 10) tapering, with two mesa1 and four lateral spines; mucrones



================================================================================

222 PSYCHE. [July, WI
(figs. 9-11) five sixths ;is long as the dentes, lanceolate from the sidc. linear from above, serrate with entire apex. Head find body naked, excepting a few still anal setne; 1113- pendages sparsely clothed with minute stiff setae. Miixiininn length, 0.56 mm.
Described from twenty-one types, some
of which have been given to the Museum
of Compaiative Zoology at Cambridge.
Mass.
Neelus -fnurhms.
Fig. I. Left aspecl of Iel'L hind leg, X 118. Fig. L Diqram of a sagittal section sliovv- iny the peculiar alimentary canal of the genus, X us.
Fig. 3. Lateral aspect, X 122.
Fig. 4. Latcrsil view of left antenna, X 506.
Fi" .;. Right aspect of 1-ight fore foot, X 1008.
Fig. 6. Right aspect of right hind foot, X 1008.
Fig 7. Veiitri-.il tube as seen from the left side, X 269.
Fig. 8. Vetiti-:tl tube showing exsertile papillat;, X 448.
Fig. 9. Furnila. x 269.
Fig. 10. Furctila, ftom above, X 224.
Fig. 11. Right aspect of left ~nucro, X 605. MICRODON LARVAE IN PSEUDOMYRMA NESTS.*
BY WILLIAM MORTON WHF.F.I.ER, AUSTIN, TEXAS. The larvae of the Syrphid flies belong-
ing to the genus Microdon are of pecul-
iar interest to the entomologist both on account of their occurrence in ant
nests
and because of their remarkable appear-
ancc which is more like that of slugs,
planarians or scale-insects than Dipteron larvae. In Europe they have long been
known to occur in the nests of several
Formiciclae and even in the nests of
Vespa crabr0.t
Wasmann.t records the occurrence of
the larva ancl pupa of Microdon mulabilis L. with Formka fusca, F. rub, F. 7-yIfi- barhi,?, L&s ntker, L. hrnn'fu'us aiid L. /?mus, and of ^icrodon dcviii-s L. with .F. fnsca, I<\ sflup~inea, F. rztfa (nui L.ful'igi- noszis. Acllerz$ Iound a species in the
nest of Ca?npo^iufus he7mZeanus. 111 the Unilecl States Microdon larvae arc occa- sionally found with Ca.rnfo/~oius pem7syl- ~~anicits ancl Formica infq-a, and a care-



================================================================================