THE DIPTEROUS GENUS ZYGOTHRICA OF WIEDEMANN. 



A. H. Sturtevant, 

 Of Columbia University, New York City. 



In the year 1830 Wiedemann ^ described a Brazilian fly under the 

 name of Achias dispar, the genus Achias being placed in the family 

 Diopsidae. This species was so placed on account of its broad head 

 with conically produced eyes. Wiedemann stated that this char- 

 acter is much more marked in the male than in the female. In the 

 same year he published a revision of the species of the genus Achias., 

 in which he made A. dlspar the only species of a new genus, called 

 ZygothHca.^ 



Two years later Gray ^ published a figure of the species. It was 

 again figured by Macquart.* Macquart^ discussed the species, and 

 placed it doubtfully in his family Lauxaniidae. It does not seem 

 certain from his account that he had seen a specimen. The figure 

 is perhaps a copy of that of Gray, and the description may have been 

 taken from that of Wiedemann. 



The next reference to Zygothrica was by Loew.*' He had seen a 

 specimen that was perhaps Z. dispar, and on the basis of that speci- 

 men referred the genus doubtfully to the Drosophilidae. Bigot ^ 

 tabled the genus among the Diopsidae, apparently without having 

 seen it. Osten Sacken ^ stated that he had seen a specimen that made 

 on him the impression of a Drosophilid. 



Hendel" mentioned the genus in connection with Plagiocephalus 

 Wiedemann. The latter is an Ortalid genus that was also based on 

 a Brazilian species first described by Wiedemann as an Achias. Hen- 

 del had apparently not seen Zygothrica^ but suspected that it might 

 possibly be an Ortalid. Two years later, however," he had seen 



» Aussereurop. Zweifl., vol. 2, p. 556. 



" Achias Dipt., Genus 10, p. 3. 



s Animal Kingdom, vol. 2, p. 774, 18.32. 



* Dipt. Exot., vol. 2, pt. 3, pi. 34, fig. 2, 1843. 



5 Idem., p. 409. 



« Mon. N. Amer. Dipt., vol. 3, p. 23, 1873. 



'Annales, p. 91, 1880. 



8 Dipt. Malay Arch., p. 90, 1881. 



»Gen. Insect., p. 113, fasc. 52, 1911. 



lODeutsch. Ent. Zeit., p. 633, 1913. 



Proceedings U. S. National Museum, Vol. 58-No. 2330. 



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