2. Disc of mesonotum silvery gray pollinose 3 



— Disc of mesonotum brownish 4 



3. Mesofrons shining; Inyo and San Bernardino counties 

 salinaria Sturtevant and Wheeler 1954 



— Mesofrons dull; Great Basin of California 



nivosa Cresson 1935 



4. Bristles fine, acrostichal setulae minute; California 

 dichaeta (Loew) 1860 



— Bristles stout, acrostichal setulae strong; Inyo and 

 Lassen counties cephalotes Cresson 1935 



5. Mesofrons shining; California seacoast 



quadrisetosa (Becker) 1896 



— Mesofrons dull; California sibilans (Haliday) 1833 



475 

 Wirth and Stone: Diptera 



REFERENCES 



\LDRICH, J. M. 



1912. Tne biology of some western species of the dip- 

 terous genus Ephydra. Jour. N.Y. Ent. Soc, 20:77-99. 

 3ERG, C. O. 



1950. Hydrellia (Ephydridae) and some other acalyptrate 

 Diptera reared from Potamogeton. Ann. Ent. Soc. 

 Amer., 43:374-398. 



3EYER, A. 



1939. Morphologische, Okologische und physiologische 

 Studien an den Larven der Fliegen: Ephydra riparia 

 Fallen, E. micans Haliday und C'dnia fumosa Sten- 

 hammar. Kieler Meereforschungen, 3:265-320. 



3C-HART, G. E., and J. E. GRESSITT 



1951. Filth-inhabiting flies of Guam. B. P. Bishop Mus. 

 Bull. 204, 152 pp., 17 pis. 



30LWIG, N. 



1940. The description of Scatophila unicornis Czerny 

 1900 (Ephydridae, Diptera). Proc. Roy. Ent. Soc. 

 London (B), 9:129-137. 



3RAUNS, A. 



1939. Zur Biologie der meerestrandfliege Scatella sub- 

 guttata Meig. (Familie Ephydridae: Diptera). Zool. 

 Anz., 126:273-285. 



:rawford, d. o. 



1912. The petroleum fly in California, Psilopa petrolei 

 Coq. Pomona Coll. Jour. Ent., 4:687-697. 



:resson, e. t., jr. 



Synopses of North American Ephydridae. 



1942. (Diptera). I. Psilopinae. Trans. Amer. Ent. Soc, 

 68:101-128; 



1944. II. Hydrelliini, Hydrinini and Ilytheini. 70:159-180; 



1946. III. Notiphilini. 72:227-240; 



1949. IV. Napaeinae. 74:225-260. 

 3RUNBERG, K. 



1910. Diptera, In: Brauer, A. Die Susswasserfauna 

 Deutschlands, Heft 2 a, Jena. 

 1ENNIG, W. 



1943. Ubersicht iiber die bisher bekannten Metamorpho- 

 sesstadien der Ephydriden. Neubeschreibungen nach 

 dem Material der Deutschen Limnologischen Sunda- 

 expedition (Diptera: Ephydridae). Arb. Morph. Tax. 

 Ent. Berlin-Dahlem, 10:105-138. 



rOHANNSEN, O. A. 



135. See Diptera references. 

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



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

 1:1-189. 

 r/HORPE, W. H. 



1931. The biology of the petroleum fly. Science, 73: 

 101-103. 

 rUXEN, S. L. 



1944. The hot springs, their animal communities and 

 their zoogeographical significance. The Zoology of 

 Iceland. 1(11): 1-206, 7 pis. 





Fig. 14:60. Canaceidoe. a, Proconace nigroviridi s Cress., 

 adult female; b-d, Canaceoides nudata (Cress.): b, egg; c, 

 puparium; d, larva (Williams, 1938). 



WILLIAMS, F. X. 



1938. Biological studies in water-loving insects. Part 

 HI. Diptera or flies. A. Ephydridae and Anthomyiidae. 

 Proc. Hawaii. Ent. Soc, 10:85-119. 



Family CANACEIDAE 



This small family of "beach flies" is closely related 

 in appearance and habits to the preceding family, the 

 Ephydridae. However, canaceids are almost exclu- 

 sively intertidal in habit, only two fresh-water species 

 having developed in the torrential mountain streams 

 of Hawaii and the East Indies (Wirth, 1951). The 

 adults (fig. 14:60a) are quite ephydridlike, especially 

 in the structure of the head, with the large mouth and 

 proboscis and exposed clypeus, but with important 

 differences in wing venation and abdominal structure. 

 The larvae (fig. 14:60c?) differ from the ephydrids 

 principally in the unbranched posterior air tube with 

 three openings to each posterior spiracle and the 

 presence of one well-developed, spinose, anal proleg. 

 Williams (1938) has given us practically the only 

 detailed description of the immature stages and 

 biology of the Canaceidae in an important, well- 

 illustrated paper on the Hawaiian fresh-water Pro- 

 canace nigroviridi s Cresson and on Canaceoides 

 nudata (Cresson) (fig. 14:696-d), which also occurs 

 along the United States Pacific Coast. 



Key to the North American Genera of Canaceidae 



Adults 



1. Mesofrons with at least 2 pairs of long interfrontal 

 bristles; prescutellar acrostichals present; posto- 



cellars strong Canace Haliday 



— Mesofrons with 1 pair of bristles, just outside ocellars; 



