ENTOMOSTEACA OF MINNESOTA. 



103 



mm., stylets 0,14 mm., last two abdominal segments 0.16 mm., antennae 

 0.7 mm., first segment of body 0.5 mm. The basal segment of the 

 antennae is long and ornamented with several transverse series of 

 spines; the last two segments are equal and longer than the preceding. 

 The armature of the first and fourth feet is identical with C. thomasi, 

 as is the form of the female openings and the fifth feet. The form of 

 the first feet, caudal stylets and other details were correctly figured 

 on Plate V of the Oyclojndce of Minnesota. 



Specimens of Qyclops pidchellus (thomasi) y^evo, obtained from a cistern 

 which is supplied solely by rain-water. The eggs must have been in- 

 troduced in ice which had been placed in the cistern at least a year 

 previously. The cistern is entirely dark, so that these animals must 

 have been deprived of light for many generations. The general color 

 was, of course, very white; the eye spots were pale, but present with 

 some pigment and the lenses. No noticeable alteration in form had 

 resulted. 



* Cyclops iiiiuniliis Forbes. 

 Forbes '93. 



A small slender species with 17 jointed antennce, with narrow and 

 loosely articulated cephalothorax and salient thoracic angles, slender 

 abdomen, long narrow farca, and but two well -developed caudal setae 

 for each ramus. The antennae reach to the posterior margin of the 

 second distinct segment, and are of very nearly the length of the ab- 

 domen (excluding the caudal setae). The greatest width of the thorax 

 is contained two and one third times in its length, and the furca is 

 very nearly half the length of the remainder of the abdomen. The 

 diameter of a ramus is about one seventh its length. 



The rudimentary inner caudal seta is a trifle longer than the outer, 



and about a third the length of the ramus; the longest seta as long as 



abdomen and furca; the next in length less than half the longest. The 



armature of the legs is as follows: 



First Feet. 

 1 seta. 



1 spine 2 setae. Inner ramus 



2 setae. 

 Second Feet. 



2 spines. 

 1 spine, 1 seta. Inner ramus 



3 setse. 

 Third Feet. 



1 spine. 

 *2 spines, 1 seta. Inner ramus 



3 set re. 



Fourth Feet. 



1 spine. 

 *^2 spines, 1 seta. Inner ramus 



Outer ramus 



Outer ramus 



Outer ramus 



ex. 

 ap. 



ex. 

 ap. 

 in. 



ex. 

 ap. 

 in. 



ex. 

 ap. 



in. 



ex. 

 ap. 



1 seta. 



1 spine, 1 seta. 



3 setoe. 



1 seta. 



1 spine, 1 seta. 



3 setpe. 



1 seta. 



1 spine, 1 seta. 



3 set;©. 



Outer ramus 



ex. 

 ap. 

 in. 



3 setfe. 



1 seta. 

 *2 spines. 



2 setse. 



• In each case one spine twice as long as the other. 



