478 



Wirfh and Stone: Diptera 



Genus Dictya Meigen 



The immature stages of Dictya pictipes Loew have 

 been described and figured by Needham (in Needham 

 and Betten, 1901). They were taken under floating 

 vegetation at the edge of a pond in New York. Peter- 

 son (1951) also figured the larva of Dictya (fig. 

 14:61c). The species can be separated only on the 

 basis of the male genitalia. 



lobifera Curran 1932. 

 umbrarum (Linnaeus) 1758. 

 umbroides Curran 1932. 



Yosemite 

 Central California 

 Central California 



Genus Poecilographa Melander 



Johannsen (1935) has described the puparium of the 

 only American species, P. decora (Loew), which was 

 found in a bog in the woods. 



Genus Tetanocera Latreille 



Johannsen (1935) has published a description of the 

 immature stages of T. ferruginea Fallen. He took 

 puparia, from which this species was reared, floating 

 on the water surface under overhanging vegetation on 

 a pond margin. Nielsen et al. (1954) figured the larvae 

 of S. robusta Loew from aquatic environments in 

 Iceland. 



California species: 



obtusifibula Melander 1920. 

 plebeia Loew 1862. 



vicina Macquart 1843. 



Santa Clara County 



Humboldt County, 



Lake Tahoe 



Widespread in California 



Genus Limnia Robineau-Desvoidy 



pubescens (Day) 1881. 

 saratogensis saratogensis (Fitch) 



1856. 

 saratogensis severa Cresson 



1920. 



REFERENCES 



Shasta County 

 El Dorado, Lake 



Shasta County 



BERG, C. O. 



1953. Sciomyzid larvae (Diptera) that feed on snails. 

 Jour. Parasit., 39:630-636. 



CRESSON, E. T., JR. 



1920. A revision of the Nearctic Sciomyzidae (Diptera, 

 Acalyptratae). Trans. Amer. Ent. Soc, 46:27-89, 3 pis. 

 JOHANNSEN, O. A. 



1935. See Diptera references. 

 MELANDER, A. L. 



1920. Review of the Nearctic Tetanoceridae. Ann. Ent. 

 Soc. Amer., 13:305-322, 1 pi. 

 NIELSEN, P., O. RINGDAHL, and S. J. TUXEN 



1954. The zoology of Iceland. Vol. Ill, part 48a. Diptera, 

 1:1-189. 



PETERSON, A. 



1951. See Diptera references. 



STEYSKAL, G. C. 



1950. The genus Sepedon Latreille 

 (Diptera: Sciomyzidae). Wasmann 

 271-297. 



in the Americas 

 Jour. Biol., 8: 



Family SCOP EUMATIDAE 



(=CORDILURIDAE or SCATOPHAGIDAE) 



Most of the Scopeumatidae or "dung flies" live in 

 dung and decaying vegetation, although a few species 

 are known to be leaf miners and stem borers. At least 

 two genera have been taken boring in underwater 

 stems of aquatic plants and should be considered 

 here. Johannsen (1935) records a third genus, Acan- 

 thocnema, which was taken in a tent trap over a brook, 

 and it may also be aquatic. 



The larvae (fig. 14:62c) are whitish and fusiform, 

 largest in diameter before the middle and gradually 

 tapering caudad, the last segment somewhat pointed; 

 the mouth hooks are blunt, broad at the base, and 

 not serrate (fig. 14:626); the anterior respiratory or- 

 gans (fig. 14:62e) are cribriform or fan-shaped and 

 each bears about 35-40 small openings. The puparium 

 is rather straight dorsally, with the pointed caudal 

 end bent upward, the ventral side arched; the integ- 

 ument is longitudinally and transversely wrinkled, 

 with a number of conical papillae between the spi- 

 racular disc and the anal plate. 





Fig. 14:62. Hydromyza confluens Loew, larva, a, caudal view 

 of spiracular plates; b, pharyngeal skeleton; c, laterol view; d, 

 spiracular plate, lateral view; e, anterior spiracle (o,b, Johann- 

 sen, 1935; c-e, Needham, 1907). 



