Article beginning on page 497.
Psyche 6:497-498, 1891.

Full text (searchable PDF)
Durable link: http://psyche.entclub.org/6/6-497.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.
THE PRIMITIVE NUMBER OF MALPIGHIAN VESSELS IN INSECTS.- 111.
BY WILLIAM MORTON WHEELER, PH.D., CHICAGO, ILL. ORTHOPTERA, It is in this order
that we first meet with facts having a
-
decided bearing on the question under
consideration. I have no data on the
embryology of the Phasmidae and Man-
tidae.* The other families may be taken
up in order.
BLATTIDAE. In the embryo PhyZZo-
dromia germanica I find four Malpig-
hian vessels which arise as discrete
outgrowths of the hind-gut in the
manner so often described for other
insects. Somewhat later two more
vessels are added. The adult Phyllo-
dromia and Peritlaneta orientalis have
60-70 vessels according to Schindlert
and~iall and Denny. $
Hence a great
increase in the number of tubules must
take place during larval life.
That this
is the case was shown by Schindler,$
who found only 16-18 vessels in a larval Periplaneta not quite 10 mm. long, and
only eight vessels in larva measuring
4-5 mm. Notwithstanding this increase
in the number of vessels, the number
*Leon Dufour. Recherches sur les Orthoptferes etc., p. 358, claims the number of Malpighian vessels in the adult Mantis to be "une cenlaine environ." 7 1. c. p. 607.
+ The structure and life-history of the cockroach (Peri- planeta orientalis) London, 1886, p. 128. $1. c. p. 607.
(6) persists throughout life, since, as
Miall and Denny* have shown, the
vessels of the adult are grouped in six
clusters at the anterior end of the strik- ingly hexagonal rectum.
LOCUSTIDAE. In the embryo Xifhi-
dium ensiferum four Malpighian
vessels arise as in Blattids; to these a third pair is soon added. In the adult,
of which I examined four specimens,
the vessels are inserted in six clearly
defined clusters, each containing about
7 or 8 tubules. Hence there can be no
doubt that in this form also the number
of vessels increases during larval life. This increase is probably effected by a
budding out of new vessels from the
proctodaeal wall at the bases of the em- bryonic vessels. A large adult Orchel-
imum which I examined showed the
same arrangement of Malpighian ves-
sels as Xiphidium.
Other writers have observed the clus-
tered arrangement of the excretory
tubules in the Locustidae but they fail
to find six clusters. According to Leon
Dufourf the 10-12 vessels of Ephip-
pigera open into the gut on five sepa-




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

498 ' PSYCHE. [~ugust 1893.
rate knob-like projections. According
to Schindler,* Locusta viridissima has
more than 100 vessels; "sic munden
zwar bei L. viridissima einzeln in den
anfangstheil des dunndarms ein, haben
sich aber dabei-entsprechend dem fami-
liencharakter-deutlich in 4 odes 5 ziem- lich umschriebene buschel gruppiert ."
Schindlery also studied Decticus veyru-
civorus. LDie absonderung diesel-
organe in einzelne (vier) buschel ist bei Decticus weniger auffallend, als bei
Locusta." I venture to conclude either
that Dufour and Schindler have over-
looked one or two of the clusters of
vessels or, what is more probable, that
the forms which they studied presented
a fusion of two or more of the primitive clusters.
GRYLLIDAE. The Malpighianvessels
of this group present a very aberrant
(character ; most, if not all, the forms having in their adult condition a great
number of tubules opening into the
rectum by means of a single long duct.
Schindler$ estimates the number of
vessels in Acheta c@estris at about
100.
Rathkes studied the embryonic con-
ditions in Gryllotalpa and found that
the embryo leaves the egg with only
four vessels, which, even at this time,
are connected with the proctodaeum by
means of a single duct. Soon another
pair of vessels is added, so that we really have a stage with six vessels, albeit
* 1. c. 619.
1 1. c. p. 621.
1 1. c. p. 616.
$ Zur entwicklungsgeschichte d. maulwur fsgrille. Miiller's archiv. 1844, p. 27, taf. ii, fig. 435. united in a single cluster.
More vessels
are acquired from time to time during
larval life, till the imaginal number is completed.
Oecanthus niveus apparently pre-
sents more primitive conditions. Ayers.* who studied the embryology of this
insect, makes the following statement.
"When the tube (proctodaeum) has
elongated so that its enlarged end lies
within the fourth or fifth segment of
the abdomen (counting from behind
forwards) there arises near the free end in the median dorsal line a small
trilobed, hollow bud of the ectodermic
layer, opening into the lumen of the
tube. Each lobe grows rapidly into a
small tubular organ, the primitive Mal-
pighian vessel. Each of these bifurcates at some distance from the proctodaeum,
so that there are ultimately six of the
tubes." This account certainly tends
to show that in some Gryllids 3 and 2
are combined in the primitive number.
The common duct seen in Gryllotalpa
and Acheta and indicated in the em-
bryo Oecanthus may, I believe, be
safely regarded as a secondary develop-
ment, since it occurs in no other group
of Orthoptera and but very rarely
appears in other orders.
ACRIDIIDAE. The numerous Mal-
pighian vessels in this family resemble
those of the Locustidae but are not ar-
ranged in clusters. In the embryo
Melanoplus femur-rubrum I find only
six vessels, originating simultaneously
in three pairs.
* On the Development of Oecanthus niveus and its parasite Teleas. Mem. Bost. soc. nat. hist. vol. iii, 1884, p. 246.




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