Article beginning on page 455.
Psyche 6:455-456, 1891.

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DESCRIPTION OF THE PUPA OF TOXOPHORA VIRGATA 0. S. BY C. H. TYLER TOWNSEND.
The description given below has been
drawn from a pupal skin of Toxojhora
virgata 0. S., sent me with the fly for
determination by Professor C. P.
Gillette, who bred the species at Fort
Collins, Colo., from the nest of a wasp
belonging to the genus Odynerus. Dr.
Fr. Brauer, in his work on dipterous
larvae (Denkschr. math.-natur. kais.
akad. wissensch. 1883, bd. xlvii, pp.
27-28), mentions the characters of the
pupae of the European Anthrax flava
L. and Bombylius major L., and gives
a rather diagrammatic figure of a false
pupa of Argyramoeba. tripzmcfata
Meig. Dr. T. Algernon Chapman
gave a detailed description of the pupa
of B. major five years before (Ent. mo.
mag. 1878, v. xiv, pp. 198-200) ; it has been figured by Imhoff (Isis, 1834), and later by Westwood (Intr. class. ins. v.
. .
11, p. 538). Dr. C. V. Riley has
described and figured the pupae of Sys-
toechs areas 0. S. and Triodites mus
0. S. (Rep. U. S. ent. comm. ii, pp.
267-269). These, if I am not inis-
taken, are about the only genera the
pupae of which have been described.
The following description will there-
fore be of interest as furnishing the first definition of the pupal characters in the genus Toxophora, and also as showing
the very material differences in pupal
structure between this genus and those
that have been previously studied.
It will be noticed that the pupal seg-
ment which Dr.
Brauer calls the first
abdominal, I have termed the scutellar.
I used the term merely as a matter of
convenience, and before referring to
Dr. Brauer's work. It, however, seems
preferable to designate this segment by
some other name than that used by
Brauer, since it does not pertain to any part of the abdomen of the
perfect
insect, but, dorsally, encloses the scu- tellum which belongs to the mesothorax.
I have therefore adhered to the term
scutellar segment, and designate the
segments which follow as the 1st to the
8th abdominal, the 8th being also called the anal.
Dr. Chapman must have been in
error when he stated (1. c. 200) that no parts of the perfect fly were formed in
the cephalic horns.
It is very apparent
that the first antenna1 joint of Toxo-
phora is encased in the' upper pair of
horns described below, the second joint
being reflexed beneath it, and the pecu- liar awl-shaped third joint being encased in the spine-shaped posterior process of the lower pair of horns. The upper
pair is hollow except the tips, and
divided longitudinally by a chitinous
septum.
Pupa of Toxo'phora virgata 0. S.- Whit-
ish, with more or less of a flavous tinge, especially the sternal portions and wing and leg sheaths; cephalic horns rufous
brown, tips nearly black; proboscideal sheath



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456 p5'2'THE. [May 1893.
concolorous with sternum ; anal hooks rufous brown; long lateral filamentous hairs of abdominal segments rufous, the scattered hairs in the dorsal rows of spines and on sides of venter pale rufous; dorsal rows of appressed spines rufous, darker on tips of spines ; spiracles brownish. Four cephalic horns; the upper pair (antenna1 cases)
soldered together on fully their basal two- thirds, much longer and larger than the
lower pair, straight and not hooked, stout at base, corrugated and roughened basally but smooth and polished on terminal portion ; the lower pair is very short, widely separated, and springs one on each side from the outer base of the upper pair, being continued pos- teriorly in a spine-shaped process (sheath of third antennal joint) ; each horn of the upper pair bears immediately outside its dorsal edge at base a hair arising from an ocellus-like impression, and a similar hair on the outer side less than half way to tip arising from a slight depression of the surface; each horn of the lower pair has a hair arising from the integument just below and inside its base. Sheath of proboscis closely appressed to the sternum, and extending back to a point
immediately below base of scutellar segment. Cephalic segment moulded above to the
shape of the eyes of the imago, constricted posteriorly at its junction with the thorax, with a short hair on each side at the posterior margin laterally and a little inferiorly. Thorax (the soldered proscutum and meso- scutum minus the scutellum) but little wider than head, constricted anteriorly, bulging laterally behind at wing bases ; dorso-pleural region with three weak hairs arranged in a triangle and considerably removed from each other, the upper and lower ones in a perpen- dicular line and the third posterior to this line and about equally distant from the other two; leg and wing sheaths free, extending under the abdomen, the two posterior leg sheaths extending fully to base of fifth abdominal segment (6th abdominal segment of Brauer), the wing sheaths nearly to middle of second abdominal segment; scutellar seg- ment with six or seven lateral hairs ante- riorly. Abdominal segments I to 4 of nearly the same width (the 4th but slightly nar- rower), and a little wider than scutellar seg- ment ; segments 5 to 7 successively narrower, the 7th fully one third the width of
basal segments; segments I to 7 armed on the dorsum with a median transverse row of closely set perfectly appressed posteriorly directed spines, those in the middle of the rows being a little shorter than those on the sides, each row (except the one on the 7th segment) approximated at its ends to the anterior margin and in its middle to the pos- terior margin of the segment; these rows of appressed spines are in addition sparsely set with posteriorly directed appressed hairs two or three times the length of the spines, the hairs being longest on the sides ; the lat- eral hairs on scutellar segment and those among the rows of spines on the abdominal segments are microscopically pubescent.
Scutellar segment and abdominal segments I to 6 furnished on their inferior lateral edge each with three (except 6th segment which has only two) long inferiorly and a little out- wardly directed filamentous or thread-like hairs on each side, those on the scutellar seg- ment usually directed straight outward
(instead of inferiorly) and curved suddenly forward; these hairs are nearly all much longer than the width of the segments from which they depend, except those on the 6th abdominal segment which are about as long as the width of the segment; those on the first two basal segments are considerably the longest ; a few shorter hairs spring from the lateral ventral surfaces of segments I to 6; the last are microscopically pubescent, but the long filamentous hairs are only sparsely so on their distal portions. Seventh segment with posteriorly directed appressed hairs on sides, but without hairs or only short weak ones on ventral surface. Anal segment a
little more narrowed than yth, directed some- what downward as is also the 7th, less dis-



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tinctly separated from the seventh than are the other segments from each other, without hairs, but armed with two pairs of terminal hooks; the upper or anterior pair blunt
spine-like, approximated and stout at base, somewhat appressed but not terminally
recurvate or hooked; the lower or inferior pair more removed, terminally recurved
below, sharp claw-shaped, slightly divergent, directed inferiorly; anterior to the latter on ventral surface there is a pair of small tuber- cles. Ten pairs of stigmata or spiracles, as follows : Prothoracic spiracle on side at anterior margin of prothorax ; mesothoracic spiracle on anterior border of wing bases; metathoracic spiracle in the anterior lateral angle of dorsum of scutellar segment; and an abdominal spiracle in the anterior lateral corner of dorsum of each of the abdominal segments I to 6, the 7th segment having a small median lateral one higher up on side of dorsum; the spiracles (except the mesotho- racic) appear as a corneous circle marked by radiating lines within, those on the 7th segment showing this structure less dis- tinctly, while the mesothoracic spiracle is indistinct and does not usually reveal this structure at all.
Length, 8.5 mm. (including cephalic
horns) ; width of basal abdominal segments, 2.25 mm. ; length of long filament-like hairs of 3d to 5th segments about 3 mm., those of 1st and 2d segments over 4 mm.
THE PRIMITIVE NUMBER OF MALPIGHIAN VESSELS IN INSECTS.-I.
Since the days of Schwammerdam
anatomists have most naturally evinced
far greater interest in the physiology
than in the morphology of the Malpig-
hian vessels. Hence we are in posses-
sion of a much larger body of facts bear- ing on the function than on the
phylogenetic history of these interesting organs. Their possible relations on
the one hand to the tracheee, which
have a somewhat similar orgin, and on
the other to vermian nephridia, which
have a similar function, are still
shrouded in the deepest obscurity.
Before these fundamental questions
can be answered satisfactorily, it will be necessary, I believe, to come to some
definite conclusion in regard to several minor questions. Foremost among
these is the question as to the primitive number and arrangement of the organs
under consideration.
No fact in insect development is
better authenicatecl than the derivation of the Malpighian vessels. It was
Biitschli* who in 1870 first showed that in the bee the paired excretory organs
arise as hollow diverticula of the hind- gut which itself arises as a more exten- sive invagination of the ectoderm at
the caudal end of the embryo. All
succeeding writers have confirmed this-
observation.
It is worthy of note that there is ex-
tensive variation in the time at which
the vessels make their appearance in
* Zur entwicklungsgeschichte der biene. Zeitschr. f. wiss. 2001. 20. bd. 1870, p. 541.




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