NO. 13S2. 



THE ACARTXA OR MITES— BANKS. 



87 



European genera will also be found to occur in North America. A 

 German, Doctor Koenike, published a valuable paper on some Cana- 

 dian forms, and latel}^ Dr. R. H. Wolcott, of Nel)raska, has issued 

 several excellent articles on our native species. 



Fk;. fil. — LiMNESIA SP., PAI.PUS 

 AND CDXAI. PLATES. 



Fig. 02.— Tyrellia cikci'laris. 



Living in the sea Pontardcluia, XaulardHiiKi 



Living in frenh water 2 



Eyes close together near the median lim^ 'A 



Eyes widely separate on the sides 4 



Hind legs far from front legs, and without swimming hairs; tips of tarsi ol)li(jnely 

 truncate; hody somewhat divided into cephalothorax and abdomen; in fact, 



the whole creature is trombidiform ( Limnocharinfe) Liiiinofliarcn 



Hind legs not far from front legs, with swimming hairs; tarsi pointe<l; no indi- 

 cation of di visi( >n < >f 1 » idy ( Eylaimc ) Ei/Iai}^ 



Penultimate joint of palpus prolonged beyond base of last or with a tooth or 



spine-like projection near, or at tip ( Hydrachnin;e) 5 



Penultimate joint of palj)ns not prolonged beyond base of last, nor ending in a 



spine ( Hygrobatinje) 10 



Mandibles, one-jointed, needle-like IIii<Jr<ic]nia 



Mandibles of two joints, with claw at end 6 



Lateral eyes far apart r)!plo<J<iiitiis 



Latcra^ eyes close together 7 



Without swimming hairs to legs S 



With swimming hairs !> 



Whh a median eye on front ]iart Tliii<;f< 



Without median eye Pinii^m^ 



With a median eye on front part ILidnj)>h(t]il(A 



Without median eye TanaogudthuH 



Fiftii joint of palpus forming a claw opposal)le to the apical part of the fourth 



joint; males frequently have the abdomen extendtd behind 11 



Fifth joint of palpus not forming a claw opposable to the apical i)art of fourth 



joint i;> 



('ai)itulum orrostrum elongate, nf two joints; ])al]ii very small KrcinJmrd'id 



( 'apitulum short, entire , 12 



Dorsum with a furrow, following somewhat the <intline (if body; in male open 



behind .1 rromrim 



Dorsum without furrow Ste(j(n)((sj)is 



Epimera of l)oth sexes united into one plate 14 



Epimera (at least of female ) not united into one plati' 17 



