on the Hphemeride. 147 
Long. corp. ¢ 12-13, 9 12; set. ¢ 30, subim. 13, 
? 20, subim. 13; exp. al. ¢ 25-27, 9 30 mm. 
Hab.—Germany (Panzer) ; the Rhone about Geneva, 
to the further extremity of the Lake. (Pict.) 
Heptagenia sylvicola. 
Baetis sylvicola, Ed. Pict. 1865. 
Imago, y.s.s. ¢. “ Tergum thoracis luteum, meta- 
thorace flavescenti. Als vitrine, nervis lutescentibus ; 
apex ares marginalis flavescens. Pedes lutei; antici 
nigricantes. Abdomen luteum, juncturis nigricantibus, 
ultimoque segmentorum flavo. Seta fulvae a, Juncturis nigri- 
cantibus. Forceps nigricans.” (Hd. Pict.) Venter serie 
macularum trigonalium, quarum apices ante diriguntur. 
9. “Simillima mari. Processus ventralis penultimi 
segmentorum abdominis integer.” (Ed. Pict. & e fig.) 
Long. corp. ¢ 12, 2 18; exp.al. ¢d 31, 9 33 mm. 
Hab.—San Ildefonso, in July (Ed. Pict.). 
Heptagenia volitans. 
(Genitalia maris, Pl. VI. fig. 20.) 
H. volitans, Ktn. 1870. 
Imago, v. v. s. 3. Oculi supra fusco-picei, subtus 
testacel. Thoracis tergum atro-fuscum. Ale vitrine, 
nervis atris, tribus prioribus longitudinalium nigricanti- 
bus exceptis; apex are marginalis Vix virescenti-griseo 
tinctus. Pedum antici tibiis tarsisque fuscis, et femoribus 
obscure bicinctis; posteriores fumato-luridi, femoribus 
saturate carneo bicinctis, tarsis fuscis, et interdum tibiis 
testaceis. Abdomen supra fuscum, apicibus segmentorum 
fuliginoso-fuscis, maculisque trigonalibus lateralibus satu- 
rate virescenti-griseis : subtus satur ate virescenti- -griseum ; 
immaculatum, vel perraro locis plexoram nervorum stri- 
gisque sequentibus duabus vix obscure indicatis ; inter- 
dum quoque infra penultimum segmentorum note L-for- 
matz duz fusce sunt. Sete pallide virescenti-grisex, 
juncturis atris vel atro-fuscis. 
Long. corp. g¢ 12-15; al. 13-14; set. 25-28 mm. 
Hab.—The Thames above Pangbourne, and the Holy- 
brook near Reading; in May. ‘The name has reference 
to a habit ot the Heptagenie of hovering steadily when 
there is a gentle breeze. 
L2 
