214 kobert h. wolcott: 



least pronounced and is longest. Each has a very inconspicuous tooth in 

 the middle of the flexor margin. 



The genital area is circular in general outline and is situated toward 

 the posterior end of the body. It includes a genital cleft, flanked on 

 either side in the male by one genital plate, in the female by two. The 

 genital plates of the male are each lunate in form and bear six acetabula 

 placed in two groups with a moderate interval between. In the female a 

 transverse division along this line separates each plate into two, of which 

 the anterior is irregularly quadrilateral, the posterior roughly triangular 

 in outline, each bearing three acetabula. 



MEASUREMENTS OF SPECIMENS DESCRIBED: 



Male Female 



Length of body 0.70 mm. 1.08 mm. 



Length of palpus 0.44 mm. 



Length of leg 1 0.73 mm. 0.82 mm. 



Length of leg II 1.00 mm. 1.14 mm. (approximate) 



Length of leg III 0.98 mm. 1.15 mm. " 



Length of leg IV 1.18 mm. 1.41mm. 



Length of mandible 0.292mm. 



Length of genital area, me- 

 dian cleft 0.21 mm. 0.17 mm. 



Types retained in the collection of the author. 



This species was taken in the dredge at Lake St. Clair, Sep- 

 tember 1, 1893; later another was discovered in material 

 collected a few days previous; and others were afterward col- 

 lected in the vicinity of New Baltimore, Mich. Altogether six 

 specimens were secured, but owing to breakage in transit of the 

 bottle containing them, only two are available for description, 

 and these, a male and a female, are to a certain extent distorted 

 in mounting. Field notes taken at the time say : ' ' Pinkish 

 tinge to epimera and genital area. Legs and palpi blue of an 

 unusally deep tint. Body deep olive brown, with a yellowish- 

 brown Y-shaped mark. Eyes blackish." 



4. ATAX 1NTERMEDIUS KOENIKE. 



Atax ypsilophorus van Beneden, 48; 9 et seq., PI. 



Atax Bonzi "living free," Koenike, 81a; 626. 



Atax intermedins Koenike, 82; 265: Lampert, 93; LXXIX : Piersig, 

 94b; 214: Koenike, 96a; 233: Piersig, 96; 40: id., 97; Lief. I, 46, PL I, 

 f. 2, a-e. 



A. intermedins is one of the smaller species, and especially small are 

 the males, between which and the females there is a much greater dif- 

 ference in size than in any other of our species. The length of several of 



