Article beginning on page 539.
Psyche 6:539-540, 1891.

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October 1893.1
PSYCHE.
THE PRIMITIVE NUMBER OF MALPIGHIAN VESSELS IN INSECTS.-V.
BY WILLIAM MORTON WHEELER, PH.D., CHICAGO, ILL. NEUROPTERA. Leon Dufour* Frey
and Leuckartf-, v. Siebold \ and
Schindler 5 have shown that members
of this order have either 6 or 8 Malpi-
ghian vessels. The imaginal Sialis
has 6 vessels and the same number of
disc] ete proctodaeal diverticula is es- tablished in the embryo, as I have
observed in S. infumafa. In what
I take to be the young larva of Cov-
dalis coyzuta there are also 6 vessels
bnt in other much larger larvae (possi-
bly belonging to the genus Chauliodes)
I find the unusual number 7. This
insect, therefore, constitutes a transi- tion to the forms with 8 vessels, such
as Myrmeleon and Hemerobius.
PANORPATA. The Scorpion flies
(Panorpa) agree with Sialis in possess-
ing 6 vessels.
TRICHOPTERA. Patten 11 has shown
that the embryo Neofhylax concinnus
develops 6 Malpighian vessels as dis-
csete proctodaeal diverticula. This
number seems to be retained through-
out life by all the species of the order. 11. c. p. 627.
1. c. p. 628.
)I The development of phryganids, with a preliminary note on the development of Blatta germanica. quart. journ. micr. sci. vol. xxiv, 1884, p. 590. COLEOPTERA. Schindler * makes
the following general statement in re-
gard to this order : "Vier Malpighi'sche gefasse finden sich durchgehends bei
den Pentameren, wogegen den Hetero-
meren, Tetrameren und Trimeren stets
sechs zukommen." This assertion ap-
pears to require some qualification,
since the Pentameron Hydrophilus has
6 Malpighian vessels according to
Vangel f- while the Heteromeron Sitaris
has only 4 according to Beauregard. $
These are very briefly the facts
derived from a study of the embryo:
in the greater number of forms the
vessels arise as 6 discrete diverticula
of the hind-gut. This has been shown
for Doryphora by myself$, for Melo-
lontha by Voeltzkow 11 and for Hydro-
philus by Heider.7 In the embryo
el. c. p. 629 (foot note].
'f Beitrage zur anatomic, histologie u. physiologic des verdauungsapparates des wasserkiifers (Hydrophilus piceus, L.) Nat. hefte. Pest. bd. 10, 1886. 1 Recherches sur les insectes vdsicants. i partie, anatomic. Journ. anat. phys. Paris. 21. Annee 1885- 1886.
$The embryology of Blatta germanica and Dory- phora decem-lineata. Journ. morph. vol. iii, no. 2. 1889.
11 Melolonthavulgaris. Ein beitrag zur entwickelung im ei der insecten. Arb. a. d. zool. zoot. inst. in Wiirzb. bd. ix. heft 1. 1889.
(Plate v. figs 1, 2 & q.)
V Die embryonalentwicklung v. Hydrophilus piceus, L i. theil. Jena. 1S89.




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540 PSYCHE. [October 1893.
Dytiscus fasciventris I find only 4
vessels, and this number is retained in
the imago.
Melolodha vulgaris deserves spe-
ĺ´cia mention, as it shows that the tet- ranephric is a modification of the
hexanephric condition. Voeltzkow,
as I have said, found 6 Malpighian
vessels in the embryo of tins Scarabaeid, whereas writers on the adult and larva
describe only 4. A pair of vessels
must, therefore, be suppressed dur-
ingpost-embryonic development, $re-
sumably in early larval life. The
bearing of this fact on the tetranephric condition of Dytiscus is obvious ; we
have only to suppose that the tendency
to suppress a pair of vessels has been
carried back into early embryonic life.
LEPIDOPTERA. Schindler * and Chol-
odkowsky + have given us a consid-
erable body of facts on the number
and disposition of the Malpighian ves-
sels in the Lepidoptera. The em-
bryonic development of the tubules
was elucidated by Hatschekt, as long
ago as 1877. "Wir finden" says this
investigator, "4m stadium C schon 6
Malpighi'sche drusen, jederseits drei,
die nach hinten zuruckgebogen, rings
urn den hinterdarn1 auf dem quer-
schnitte sich zeigen (figs. 3 and 4, pi. lii) . Die drei Malpighi'schen drusen
jeder seite miinden durch ein gemein-
schaftliches aufangsstiick in das blinde ende des hintei-darmes." Hatschek's
figures show the arrangement of the
* 1. c. p, 646 et seq.
f 1. c.,
3 BeitrSge zur entwicklungsgeschichte der Lepi- dopteren. Naumburg, 1877, p. 19.
vessels to be the same as in the larva and imago. My own observations on em-
bryos of Platysamia cecropia confirm
his account.
With the exception of a very few
species, to be considered presently, all Lepidoptera have 6 Malpighian vessels.
They are not discrete diverticula of the hind-gut, but on either side two of the
vessels are united by a common trunk
to the third, so that there is only one
opening into the rectum on either side.
This antler-like system appears to arise in the following manner : a hollow bud
grows out from the proctodaeum and
bifurcates ; then one of the two vessels thus formed bifurcates, while the other
simply lengthens. Cholodkowsky calls
the duct leading into the rectum the
Lbtronc basilaire," the one uniting the
two terminal vessels the btronc second-
aire." He gives an extended account
of the relative variations in length of
the two trunks throughout the various
families of Lepidoptera. The varia-
tions are sometimes considerable, but
the number 6 is rigorously adhered to.
The only exceptions observed by
Cholodkowsky are the Pyralid Galleria
and certain Tineids.
In G. melonella the Malpighian ves-
sels resemble two trees b6richement et
irrkgulih-ement ramifibs." This pecu-
liar form is so strikingly unique that we may put it down without hesitation as
a secondary development. Cholod-
kowsky finds that the larva of Tinea
biselliella has the typical 6 Malpighian vessels; but these break down during
the pupal stage and in their stead arises



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October 1893.1 PSYCHE. 54 1
a single pair of imaginal tubules. The
Russian investigator has established the same interesting fact for Tinea /ellion- ella and Blabo-phmes rusticella.
On these cases, avowedly exceptional
even among Tineidae, Cholodkowsky
bases his dinephric hypothesis. The
return in the imago to an apparently
simpler condition of the Malpighian
vessels than obtains in the larva, is re- garded by him as a kind of atavism.
To characterize this form of reversion,
which is regular and periodic in its
occurrence, he introduces the term
cbatavisme p6riodique." But it is clear
that this atavism, if atavism it be,
must extend to ancestral conditions ex-
ceedingly remote-postulating 2 as the
primitive number of Malpighian tubules
in Arthroppds-since the number 2 oc-
curs only in very few insects, and only
in cases where a secondary reduction
from a greater number furnishes a more
plausible explanation (Coccidae) .
Cholodkowsky assumes that the basal
trunk represents the primitive Mal-
pighian vessel. I would regard both it
and the secondary trunk as compara-
tively recent acquisitions, since 1 find it difficult to see, on Cholodkowsky's sup- position, why the number of vessels
should be so constant throughout the
order and at the same time agree with
the number observed in the older and
more primitive orders (Orthoptera,
Neuroptera, Panorpata) . Moreover, it
is generally admitted that the Trichop-
tera stand very near the hypothetical
ancestral Lepidopter, and it has been
shown that both the embryo and im-
aginal Trichopter have 6 discrete
Malpighian tubules. On Cholod-
kowsky's supposition it would be
necessary to regard the urinary vessels
in the lower orders as less primitive
than those of the Lepidoptera, an as-
sumption which certainly has very little in its favor when we stop to consider
the extent to which other organs have
been modified in the Lepidoptera.
ENTOMOLOGICAL NOTES.-The 13th part
of Kolbe's Einfuhrung in die kenntnis der in- sekten completes the first volume of the work, and with it the account of the morphology and physiology of insects ; it concludes with a bibliography of the organs of generation. Although only two of the twelve main divi- sionscontemplated have been treated, another volume will doubtless complete the work. In the Contemporary review for Sep-
tember, Weismann has a deeply interesting article on the All-sufficiency of natural selec- tion, supporting his well known views of the intransmissibility of acquired characters, and in which his main arguments are drawn
from the study of ants. "All-sufficiency" is a strong term, and if it were generally con- ceded would prove a distinct bar to progress ; working hypotheses, on the other hand, lie at its very foundation.
In recent information regarding the Cam- bridge botanic garden given in the last num- ber of the Harvard graduates magazine, Prof. G, L. Goodale speaks of the damage done by white ants as follows: "In one part of the wall the ants had taken away nearly all the wood, leaving the painted surface untouched and apparently sound. From this wall they had made their way into floor timbers
hitherto supposed to be free from any pest." Mr. Townsend (Ins. life, 5 : 317) identifies the oestrid larva described by him in the cur- rent volume of Psyche, p. 298, as
Cuterebra
fontinella Clark.




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