105 

 Day: Fphemeroptera 



Hagen, neither represented in California. The sub- 

 family is separated in the key* to the subfamilies 



of the Baetidae. 



Subfamily BAETISCINAE 



This subfamily consists of the single Nearctic genue 

 Baetisca Walsh, which is separated by the chara< 



in the keys to the subfamilies of Baetidae 



Baetisca obesa was reported from California b\ 



Eaton in Revised Monograph, 1885, p. 228, but has 

 tarsi. In the hind wing the costal angulation is acute not subsequently been taken in this state, 

 and the Of is not forked. Forceps are four-jointed. 



Fig. 3:28. o, Pseudocloeon sp ?, labium of nymph; b, Para- 

 cloeocfes abditus. labium of nymph; c, Apobaeti's indeprensus, 

 labium of nymph. (W. C. Day). 



Key to the Genera 

 Nymphs 



; 1. Claw of fore leg bears several long spines; a fleshy 

 appendage is attached to inner margin of fore coxae; 

 margins of gills smoothly oval Ametropus Albarda 



— Claw of fore leg without spines; margins of gills 

 fissured Metreturus Burks 



Subfamily METRETOPINAE 

 This subfamily is not represented in California. 



Key to the Genera 



Adults 



A single pair of cubital intercalates in fore wing; 

 costal angulation of hind wing acute 



Metretopus Eaton 



Two pairs of cubital intercalates in fore wing; costal 



angulation of hind wing obtuse 2 



Fore tarsus of male fully 3 times the length of the 

 tibia; basal joint of fore tarsus of male slightly longer 

 than the second; subanal plate of female obtuse .... 



Siphloplecton Clemens 



Fore tarsus of male only about twice as long as tibia; 

 basal joint of male fore tarsus three-fourths of second; 

 subanal plate of female excavated apically 



Pseudiron McDunnough 



Known Nymphs 



1. Tarsi longer than tibiae; maxillary palpi 2-jointed 



Metretopus Eaton 



— Tarsi subequal to tibiae; maxillary palpi 3-jointed 

 Siphloplecton Clemens 



Subfamily OLIGONURIINAE 



This subfamily is represented by two genera in the 

 Nearctic region, Oligoneuria Pictet and Lachlania 



REFERENCES 



BURKS, B. D. 



1953. The mayflies, or Ephemeroptera, of Illinois. Bull. 

 Illinois Lab. Nat. Hist., 26:1-216, figs. 1-395. 

 DAY, W. C. 



1952. New species and notes on California mayflies. 

 Pan-Pac. Ent., 28:17-39, 47 figs. 



1953. A new mayfly genus from California. Pan-Pac. 

 Ent., 29:19-24, 13 figs. 



1954. New species and notes on California mayflies II. 

 Pan-Pac. Ent., 30:15-29, 14 figs. 



1954. New species of California mayflies in the genus 

 Baetis. Pan-Pac. Ent., 30:29-34, 8 figs. 



1955. New genera of mayflies from California. Pan-Pac. 

 Ent., 31:121-137, 27 figs. 



EDMUNDS, G. F., JR. 



1948. A new genus of mayflies from western N. A. 

 (Leptophlebiinae). Proc. Biol. Soc. Wash., 61:141-148, 

 i6 figs. 



1950. New records of the mayfly genus Baetodes, with 

 notes on the genus. Ent. News., 61:203-205. 



IDE, F. P. 



1941. Mayflies of two Neotropical genera, Lachlania 

 and Campsurus, from Canada. Canad. Ent., 73:153-156, 

 3 figs. 

 MAYO, VELMA K. 



1939. New western Ephemeroptera. 

 145-154, 21 figs. 



1951. New western Ephemeroptera 

 27:121-125, 10 figs. 



1952. New western Ephemeroptera 

 28:93-103, 11 fig's. 



1952. New western Ephemeroptera IV. 

 28:179-186, 11 figs. 

 NEEDHAM, J. G., J. R. TRAVER, and Y. HSU. 



1935. The biology of mayflies. Ithaca, N.Y.: 

 SPIETH, HERMAN T. 



1933. The phylogeny of some mayfly genera. 



Ent. Soc, 41:55-86; 327-390, pis. 16-24. 

 1937. An Oligoneurid from North America. Jour. N.Y. 



Soc, 65:139-145, 11 figs, 

 1941. Taxonomic studies on the Ephemeroptera II. 



genus Hexagenia. Amer. Midi. Nat., 26:233-280,62 figs. 

 UPHOLT, W. M. 



1936. A new species of mayfly from California. Pan-Pac. 

 Ent., 12:120-122, 3 figs. 



1937. Two new mayflies from the Pacific Coast. Pan-Pac. 

 Ent., 13:85-88. 



15: 



Pan-Pac. Ent., 



II. Pan-Pac. Ent 



III. Pan-Pac 



Pan-Pac. 



Ent. 

 Ent. 



Comstock. 

 Jour. N.Y. 



Ent. 



The 



