184 CALIFORNIA ACADEMY OF SCIENCES. 



Isotoma palustris Miiller var. balteata Reuter. 



Dirty white-yellow, with dark transverses on all the 



truncal segments. The eyes are sixteen, eight on each side 

 of the head. The antenna? are twice as long as the head, 

 and have the three outer joints all of the same length. The 

 third abdominal segment is about as long as the fourth. 

 The upper claw is unarmed. The lower claw is provided 

 with a little tooth, directed upwards. The mucro is pro- 

 vided with four hooks, three of which are placed in a row 

 one after another and the fourth on the outside of the seg- 

 ment. The body is densely clothed with short and simple 

 hairs. Length 1.25 mm. 



Syn. 1893, Isotoma palustris Miiller var. balteata Reut., 

 Zur Syst. u. Verbr. palsearct. Coll., p. 66. 



Of this well marked variety, which has been found 

 before only in Finland, my material contains twenty indi- 

 viduals, found by Dr. G. Eisen in the vicinity of Lake 

 Chabot, near Oakland, California. 



Isotoma fimetaria (Linn.) Tullberg. 



White. Eyes are wanting. The terminal joint of the 

 antenace is about twice as long as the preceding one. The 

 third abdominal segment is shorter than the fourth. The 

 claws arc unarmed. The mucro is provided with two 

 hooks. Length 1 mm. 



From other species with short caudal appendage /. 

 fimetaria (Linn.) Tullb. differs in the absence of eyes and 

 in its pure white color. 



I am much inclined to think that Packard, when de- 

 scribing /. nivalis, has had before him the above species. 

 The author signifies it as "a species combining some of 

 the characters of Lipura, Achorutes and Isotoma." 



Habitat. San Francisco. (Coll. G. Eisen.) 



