ENTOMOSTEACA OF MINNESOTA. 99 



middle of the outer margiu, outer termiual seta short, the outer 

 median seta as long as the innermost, inner median a little longer. 

 Antennte long, slender, reaching the middle of the fourth segment, 



some of its setse greatly elongate, formula, -—. r ^^^r^^^ ; 



the last two segments have a narrow hyaline membrane which is 

 entire. Armature of fourth feet as follows: 



{ex. 2 spines. f ex. 1 seta, 



ap. 1 spine, 1 seta. Inner ramus < ap. 2 spines, 



in. 3 set SB. (in. 2 seise. 



Fifth foot with short, broad basal joint and an oval elongate apical 

 segment bearing two setee. The receptaculum is elongate, with two 

 curved proximal branches. Length 0.87 mm. 



Cyclops di/howsJcU Lande, which seems hardly a good variety of G. 

 oithonoides, is said to differ from it in the following major points: 

 The antennae are shorter and more stout, minute difterences occur in 

 the chitin plates which unite the base of the third pair of feet and the 

 lamella of the fifth foot. In fact the differences are less than may be 

 found in any of our species when collected in different stations. 



Cyclops bisetosus Rehberg. 



Plate XXIII, Figs. 9-11. 



Sars '62 (bicuspidatus) ; Rehberg '80; Forbes '82 (insectus); Herrick '84 (insectus); 



Schmeil '92. 



Cephalothorax depressed, first segment of moderate size, angles of 

 segments rounded. Abdomen long, its length to that of the thorax 

 as 26 : 39. First segment enlarged, as long as the following. 

 Stylets long, lateral seta near the end, small teeth externally and the 

 basal one-fourth, inner and outer terminal setie small, median sette 

 rather long, the longer as long as the abdomen, the shorter two thirds 

 as long. AntenufB 17 jointed, little longer than the first thoracic seg- 

 ment. Fifth foot resembling that of C. vernalis, with a small but broad 

 basal joint with a long lateral seta, apical segment with a long seta and 

 short spine. The swimming feet are armed with three spines exter- 

 nally (0. pulcheUus has but two). Length 1.3 mm. As figured by 

 Schmeil, this species differs strongly from ('. hicuspidatns and is nearer 

 to G. parens. Whether Gyclops insectus Forbes, is really this species 

 must, in the absence of authentic specimens, be left open. 



Cyclops strenuus Fischer. 



Plate XXIII, Figs. 12, 13. 



Fischer '51; Lilljeborg '53 (quaclricornis); Claus '57 and '63 (brevicaudatus, and fur- 

 cifer); Sars '63 (scutifer, abyssorum, and strenuus); Lubbock '63 (brevicaudatus, 

 and clausii); Fric '72 (brevicaudatus); UJjanin '75 (vicinus, and fedtschenkoi); 



7 



