260 Illinois State Laboratory of Natural History. 



to have found this spine, but Schmeil confirms Forbes's state- 

 ment. The inner two spines on the last segment are serrate 

 on both margins, but this fact is shown in none of the figures, 

 nor is it mentioned in the literature referred to. The first 

 segments of the fifth pair of legs in the male are each provided 

 with a rather delicate seta near the outer distal angle. This 

 is shown in the published figures, but Lilljeborg mentioned 

 only the one on the left leg. The ordinary appearance of the 

 lamina of the second segment of the right leg is best shown in 

 Forbes's figures. 



This species is quite common in the western United States, 

 having been found to occur in considerable quantities in col- 

 lections from Nevada, Idaho, Oregon, Washington, and Mon- 

 tana, and further collections will no doubt show a still more 

 general distribution. It occurred in collections with Diap- 

 tomus ashlandi Marsh and with I), minutus Lilljeborg. 



Epischura lacustris Fokbes. 



Scopiphora vagans (?), Pickering. *4-l, p. 62. 



Epischura lacustris. Forbes, '82a, p. 648, PI. VIII., Fig. 15, 16, 21-23. 



25-27; P). IX., Fig. 8. 

 Epischura lacustris, Herrick, '84, p. 131, PI. Q, Fig. 15. 

 Epischura lacustris, de Guerne et Richard, "89b, p. 90, PJ. IV.. Fig. 



3, 9, 10. 

 Epischura lacustris, Forbes, '90, p. 704, PL I., Fig. 1-5; PI. II., Fig. 7. 

 Ejrischura lacustris. Forbes, '93, p. 255. 

 Epischura lacustris, Marsh, "93, p. 200, PI. IV., Fig. 6. 

 Epischura lacustris, Marsh, '95. p. 10, PI. II., Fig. 1-6; PI. III., Fig 



1-6. 

 Epischura lacustris, Herrick and Turner, '95, p. 82. PI. XIII., Fig. 



15. 



Of medium size. Body elliptical, widest before the middle. 

 Cephalothorax composed of six segments, the first two sub- 

 equal and together somewhat longer than the remaining four. 

 Third, fourth, and fifth segments subequal and together about 

 equal to the first. Sixth segment slightly longer than any of 

 the three preceding ; not produced laterally. Abdomen flexed 

 to the right, the first segment very short. Second segment the 

 longest and about equal to the remainder of the abdomen 



