Article beginning on page 222.
Psyche 9:222-223, 1900.

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PSYCHE.
(figs. 9-11) five sixths :IS long- as the denies, lanceolate from the side. linear from above. serrate with entire apex. Head and body
naked, excepting a few still aunl setae; ap- pendages sparsely clothed with minute stiff setae. Maximum length, 0.56 mm.
Described from twenty-one types, some
of which have been given to the Museum
of Comparative Zoology at Cambridge,
Mass.
Fig. 1. Left aspecl of (eft hind leg, X 118. Fig. 2. Diiigram of a sagittal section sliovv- ing the peculiar alimentary canal of the genus, X 118.
Fig. 3. Lateral aspect, X 122.
Fig. 4. L:iter;il view oå left antenna, X 506.
fig. ,j. Right nspect of right fore foot, X 1008.
Fig. 6. Right aspect of right hind foot, X 1008.
Fig. 7. Ventral tube 21s seen from the left side, X 269.
Fly. 8. Ventral tube showing exsertile
papilkic, x 448.
Fig. 9. Fm-cula. x 269.
Fig. 10. Furcnla, fi om above, X 224.
Fig. 11. Right aspect of left mucro, X 605. MICRODON LARVAE IN PSEUDOMYRMA NESTS.*
BY WI1.I.IAM MORTON WHEELER, AUSTTN, TEXAS. The larvae of the Syrphid flies belong-
ing to the genus Microclon 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
Formicidae and even in the nests of
Vespa crabr0.f
* Contributions from Lhe Zoological Laboratory of the University of Texas, No. 20.
+Wasiuami, Yergleicliendc Studien neber Anieisen gaeste uud Termitciigaesie Tijdaclir.voo~ Entomol. Bd. 33, 1890.
Wasrnannt records the occurrence of
the larva and pupa of Microdon ?mhbilis
L. with Formica fuses, 3. rzifa, F. ?-å´I/& barbis, Lasitis n*, Z. hn.imu:us mid L.
flaws, and of Microdon dimh L. with P.
fused, F: sanguinea, F. rufa and L./u/igi- nosus. Acllerz~ found a species in the
nest of Camponu/~ts hercz;Zea~zu.r. In [-he United States Microdon larvae arc occa-
sionally found with Campo~~o/zt.v penmy/- vanicus and furmh inte~vv, and a care-
$ Kriticlros Verzeicliniss derniyrmekophilen mid termito- philen Arlliropoden. Berlin -1894 pp. 171 and 175. $ JVIyrniecologiskcr Notiser. Eutoinol. Tirlskrift 1896 pp. 131-132.)




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July, 19011 PSYCHE. 223
ful examination of the literature would
probably show that they have also been
taken in the nests of other species of
Formiyidae in this country. Of their oc- currence in the tropics, however, little is known. Wasmann (loc. cit.) mentions
the larva of one species as occurring in Madagascar with Cam-pimotus Hilde-
bramiti, and the larva and pupa of
another as having been found in ant
nests in Australia. He also records
the occurrence of these larvae in termite nests in Madagascar and Porlo Alegre,
Southern Brazil.
During the Christmas holidays,
while collecting ants at Cncrnavaca,
Mexico, I happened on some Microdon
larvae in the nests of Pseudomyrma
graciUs Fabr. var. mexicana Emery, one
of the numerous varieties of a tropical
ant which seems to be of rather common
occurrencc from the extreme soiithwest
corner of Texas (about Brownsville
according to Townsend,*) to Rio
Grande do Sul in Southern Brazil (v.
1hering.f) In one of the Pseudomyrma
nests- which was in a hollow acacia limb and contained a deiilatcd queen, about
a dozen workers and a lot of larvae and
pupae, a mature Microdon larva was
found attached to the wall of the chamber in the midst of the ants. The other
Pseudomyrma nest was in one of the
epiphytic Til1andsias.t This contained
*On the Nogeography of Mexico and the South Western United States 11. Trans. Tex. -Acad. Sri. 1807. Vol. I1 No. I, p, 72.
?Die Amisen von Rio Grande do SuL Berlin. Entoinol. Zeitsdir. Ed. 39. Hctt. 3 1894 p. 383.
$For a description of these ~inguliir nests the reader may be referred tu my article on " Compound and Mixed Nests of American Ants,'' Am. Naturalist 190:. a Microdon pupal-ium from which the fly
had already escaped. The anterior
third of the pupa-case had been pushed
off in the manner characteristic of the
Cyclorhapha.
The occurrence of such bulky and de-
fenceless Dipteron larvae in the nestsof large-eyed, active ants like the Pseu-
domyrmas, which are, moreover, pro-
vided with powerful stings, is nearly as surprisingas their occurrence in the nests of Vespa. Apparently @he relations be-
tween the larvae and their hosts are the same us those of other species of Micro- don larvae to the less formidable ants
of Europe and the United States. Adlerz
(loc. cit.), who was able to make some
observations in Sweden, came to the
conclusion that the Microdon larvae sub- sist on the moist and tender wood, form- ing the walls of the ant galleries in pine stumps although they were also found in
burrows in the dry bark. The ants
seemed not to pay the slightest atten-
tion to the Dipteron larvae living in their midst.
Wasmann S also found that the
Erater Nachtrag zu den Ameisengaesten VOH Hollaen- disch Limbuq. Thjdcshr. voor Entomol.Dcd 49.1898 p. 7.



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224 PSYCHE. [JULY, I ~ U I
larvae of Microdon rnutatilis were com-
pletely ignored by the ants in a mixed
colony of Formica sa7z~uineafisca.
But he observed that the fly, which is
covered with delicate yellow pile, was
assiduously licked by F. san.pinea
although it soon died.
Except for this
last observation, which relates only to
its imaginal stage, Microdon may be
regarded as belonging to Wasmann's
category of synoeketic myrmecophiles,
or indifferently tolerated guests, a great company which also comprises the tiny
crickets of the genus Myrmecophila. *
The imagines of a number of species
of Microdon have been
described from
North America but they all appear to
be rare insects. They fly reluctantly
and are fond of lurking about the roots
of grasses and other plants in situations where they readily elude the observation of the most careful collector. I am un-
able to conjecture to which ot the de-
scribed Mexican species the larva ob-
served in the Pseudomyrma nests be-
longs. The ac'companying photograph
willenable any future observer to iden-
tify it without much difficulty, even if it should be found, as I have no doubt
it will be, in the nests of other species of ants in Mexico and Central America.
NOTES ON THE MATING OF ATTACUS CRCZL'OPIA AND OTHERS. BY CAROLINE G. SOULh, BROOKLINE, MASS.
In most of the large collections
of
cecropia cocoons which I have examined
the female pupae have outnumbered the
male by about five to one, twice by three to one.
For this reason I have inferred
that the males were
polygamous, and
this spring I have tested them, as the
moths emerged very early.
Close observation has convinccd me
that the female cecropia requires sixteen hours out of the cocoon before she is
ready to mate.
In no instance did a
female protrude the whole ovipositor
*See Wheeler, The Habits of Myrmecoplii1.i mbras. censis Bruiier,
Psyche, Oct., qoo. pp. 1x1-115 ; and Was- , Zur Lcbeiisweise der Ameiaeiigrillen (Myrmeco- phila). Natur u. Offenbarung- 47. Bd. 1901 pp. 729-15~). sooner, and in no instance did the male
in the cage will1 her attempt mating or
seem in the least attracted or excited
before the protrusion of the whole ovi-
positpr. Partial protrusion occurs ear-
lier.
I feel convinced that there is a differ- ent odor diffuser1 when the whole ovi-
positor is protruded, in the case of all the large Saturniids, and often I think I can detect it in spite of the previous
powerful odor of both male and female.
With one exception no female flew or
moved about the cage after her wings
were expanded until mating had taken
place, nor did any female show the least sign of noticing the male or of preference



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