A. H. Sturtevant.
The Probable Occurrence of Parthenogenesis in Ochthiphila polystigma (Diptera).
Psyche 30(1):22-27, 1923.

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Psyche [~ebruar~
Puliciphora venata Aldrich
Trans. Entom Soc. London, p. 436 (1896) (Phora). Brues. Trans. Amer. Entom. Soc., vol. 29, p. 382 (1903). (Pachyneurella)
Brues. Bull. Wisconsin Nat. Hist. Soc., vol. 12, p. 142 (1915) I cannot distinguish a series of females taken at Espia, Rio Bopi, Bolivia from the West Indian form. Dr. Mann's specimens were attracted to masses of old cheese that had been abandoned by the expedition. A number of others in my collection from Grenada, B. W. I. were similarly trapped in jars containing chicken bones to which I found them attracted in great numbers. THE PROBABLE OCCURRENCE OF PARTHENOGENE- SIS IN OCHTHIPHILA POLYSTIGMA.
(DIPTERA)
A total of 68 living specimens of Ochthiphila polystigma Meigen (one of the Ochthiphilinse. a subfamily included among '
the Acalypterate Diptera) was examined between August 23 and September 30, 1922. All were females; and there is no possibility that the males were found but not recognized as belonging to t,his species, since during that period no other member of the genus was taken. With the exception of a single female belonging to an apparently undescribed genus, the only other members of the subfamily Ochthiphilinse taken belonged to the very different genus Leucopis, and here both sexes were found. Eleven of t,he 0. polystigma female? were dissected, and three more were fixed and sectioned. In none of these was any trace of sperm found. I was during this time making a com- parative study of the structure of the internal reproductive organs of the females of all the Acalypterae, and was thus in a position to know how and where to look for sperm. It is safe to Pachc 30:22-27 (1923). hup Ytpsycht einclub orgtlW30-022 html



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19231 Probable Occurence of Parthenogenesis in Ochthiphila 23 say that none was present.
Yet several of these females con-
tained what appeared to be fully formed eggs-in fact in a number of cases there was an egg already in the uterus. Such females, evidently laying eggs but without sperm present, were found as early as August 23 and as late as the middle of September. At both times there were also found females with ovaries still small-these again being without sperm. It seems clear thus that the results are not due to the collecting having been done either at the beginning of a generation, before males had emerged or at the end of one, after the males had mated and died. In addition to the live females just discussed, I have examin- ed the pinned material in my own collection, in the collection of the American Museum of Natural History, in that of the United States National Museum, and in that of prof. J. M. Aldrich. All the specimens of 0. polystigma found in these collections were again females. The data thus obtained (including the live specimens examined) are summarized in Table I. Table I.
Distribution of Ochthiphila polystigma Meigen State or Province
New Hampshire
Ontario
Massachusetts
Connecticut
New Yorkl
New Jersey
~enns ylvania'
Maryland
Indiana
Illinois
Wisconsin
South Dakota
Manitoba
Utah
Holland
Total
Number of females
1
7
89
3
4
1
8
3
10
3
1
1
2
2
2
137
Months in which
?
May-?
June-Sept
May
Sept.
- Sept.
Oct..
Apr.-Aug.
July- Aug .
June
July
June
July
July
June
Apr.-Oct.
taken
1Two of the specimens from New York and all of those from Pennsylvania were taken by Dr. F. Schrader, and have not been seen by me. Dr. Schrader states that all were females.



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24 Psyche [~ebruar
In the collections of Prof. Aldrich and of the U. S. National Museum are specimens of four other species of Ochthiphila, identified by Coquillett and by Aldrich. These all include males,
as will appear from Table I1 (which also includes 6 European specimens from my own collection). In all four species the males have large conspicuous external claspers, and could not possibly be mistaken for females. This indicates that the failure to find males of 0. polystigma is not due to failure to recognize them as males.
Table I1 ^ Relative abundance of the sexes in Ochthiphila. Species
0. aridella Fallen
0. elegans Panzer 12 5
0. geniculata Zetterstedt 1 1
0. juncorum Fallen 5 9
A case very similar to the one just described occurs in Lon- choptera furcata Fallen. It was found by de Meijere (1906) that nearly all individuals of this species were females, and that these did not have sperm in their receptacles. In other Europ- ean species, such as L. lutea Panzer, both sexes occur in nearly equal numbers; and sperm is present in the receptacles. The extreme scarcity of males has been confirmed by Lundbeck (1916) for the European L. furcata, and by Aldrich (1918) for the American forms, which apparently belong to the same species. Aldrich was able to find only two American males of the genus (one from Ontario and one from Colorado), though he recorded 2652 females.
I have myself collected numerous American specimens of Lonchoptera, and have examined the material in the American Museum of Natural History. Table I11 shows the result of this study. The five males that appear in the table, and two of the California females as well, appear to belong to a distinct species; all the others (except perhaps the Colorado female) are almost certainly L. furcata. I have several times obtained eggs from females of this species, and these have hatched into larvse; but in



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19231 Probable Occurence of Parthenogenesis in Ochthiphila 25- no case have I been able to rear these larvae, nor have I been able to be sure that the mothers did not contain sperm-though it is extremely unlikely that sperm was present,. This obser-
vation makes it, probable, however, that Lonchoptera reproduces by adult parthenogenesis, rather than by pedogenesis. Table 111.
Relative abundance of the sexes in Lonchoptera. State or Province
New Hampshire
Vermont
Massachusetts
New York
New Jersey
Ontario
Pennsylvania
District of Columbia
North Carolina
Wisconsin
Colorado
Santa Clara Co., California
Monterey Co., California
Truckee, California
Total
Parthenogenesis has been described in the Chironomid genera Chironomus, Corynoneura, and Tanytarsus by Grimm (1870) Johannsen (1912), Goetghebuer (1913), Edwards (lglg), and others. Eggs are produced in some cases by the larvae, in others by the pupse, and in still others by the imagines. In all cases in which imagines have been produced by parthenogenetic (in- cluding pedogenetic) lines, these have been females and have bred parthenogenetically if at all. Males are known to occur in these genera, and in one case even in a species that reproduces parthenogenetiually; but in no case are males reported as arising from larvse known to have been produced by parthenogenesis. The first case of parthenogenesis recorded among the Diptera was that of the Cecidomyiid, Miastor, discovered by



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26 Psyche [~ebr uar
Wagner (1863). In this case it is the larvae that reproduce parthenogenetically. Imagines are not often produced, but when they do appear both sexes are found (Meinert 1864, Wagner 1865, Kahle 1908).
Kahle states that there is a significant excess of females, and Felt (1911) describes only the female, though he does not state that males were absent.
It is not known whether
the imagines breed at all, or not; Kahle states that he did not observe copulation.
It does not appear to have been entirely proven that the males arise from larvae that have been produced by pedogenesis, though most students of Miastor have apparently taken this for granted without making cultures from isolated larvae.
Parker (1922) has reported a probable case of pedogenesis in the blow-fly, Calliphora erythrocephala Meigen, with the production of male and female imagines in something like equal numbers from isolated individual larvae. Since the actual pro- duction of eggs or larvae was not observed to go on in Parker's larvae, and since Lowne (1892) and others have dissected large numbers of larvae of this species without finding mature eggs or larvae in them, it seems best to withhold judgment for the present as to the occurrence of pedogenesis in Calliphora, as Parker himself indicates.
LITERATURE CITED.
Aldrich, J. M. 1918. Notes on Diptera. Psyche 25; 30-35. Edwards, I?. W. 1919. Some Parthenogenetic Chironomidse. Ann. Mag. Nat. Hist. 3; 222-228.
Felt, E. P. 19 11. Miastor americana.
An account of pedogenesis.
New York State Mus. Bull. 147; 82-104.
Goetghebuer, M. 1913. Un cas de parth6nogen&se observe chez un Diptere Tendipkdide (Corynoneura celeripes). Bull. Acad. Roy. Belg. 1913; 231-233.
Grimm, 0. 1870.
~ i e ungeschlechtliche Fortpflanzung einer Chironomus-Art und deren Entwicklung aus dem unbefrucht- eten Ei. M6m. Acad. Imp. Sci. St. Peterabourg ser. 7, tome 15.




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19231 Probable Occurence qf Parthenogenesis k Ochthiphila 27 Johannsen, 0. A. 1912. Parthenogenesis and Psedogenesis in Tanytarsus. Maine Agr. Exp. Sta. Bull. 187; 3-4. Kahle. W. 1908. Die Padogenesis der Cecidomyiden. Zoologica, Bd. 21. Heft. 55. 80 pp., 6 plates.
Lowne, B. T. 1892-1895. The Anatomy, Physiology, Morphology, and Development of the Blow-fly. London. 2 vols., 778 pp. Lundbeck, W. 1916. Lonchoptera. Diptera Danica 5; 1-18. de Meijere, J . C. H. 1906. Die Lonchopteren des palaarktischen Gebietes. Tijd. v. Ent. 49; 44-98.
Meinert, F. 1864
Weitere Erlauterungen fiber die von Prof. Nic. Wagner beschriebene Insectenlarve, welche sich durch Sprossenbildung vermehrt. Zeits. wiss. 2001. 14; 394-399. Parker, G. H. 1922. Possible Pedogenesis in the Blow-fly, Calliphora erythrocephala. Psyche 29 ; 127-131. Wagner, N. 1863. Beitrag zur Lehre von der Fortpflanzung der Insect enlarven. Zeits. wiss. Zool. 13; 513-527. Wagner, N. 1865. Ueber die viviparen Gallmuckenlarven. Zeits. wiss. Zool. 15; 106-117.




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