88 



PRCCEEDINGH OF THE NATIONAL MUSEUM. 



VOL. XXVIII. 



14. Fourth joint of i)alpus with a jirojection ])el( >\v X[/ii(vtiolas 



Fourth joint of palpus without projection 15 



15. Dorsum without a bowed furrow Lehcrlia 



Dorsum with a ho^ved furrow 16 



16. Second joint of palpus with a prujeetion ])el()\v; genital aperture at tip of 



body At(iru.< 



Second joint of pal})us without projection; genital aperture nn;ch before tip of 

 ])ody }rideo})xls 



17. Fourtli tarsus without i-law; a long bristle at tij) Liinncsid 



Fourth tarsus with claw as others .^ IS 



IS. Genital opening with lip each side nearly covering the disks; paljii with spine 



l)elow on joint 2 Spcrch^ni 



Disks near genital opening fully exposed , 19 



19. Epimera of female in two groups K(viiik('(i 



Epimera of female in three groups; genital opening usually with three disks each 



side 20 



Epimera of female in four groui)s 21 



20. Apical joints of leg I normal Ili/grulxilex 



Fifth and sixth j( )ints of leg I curved A trodldes 



21. Genital opening with three disks each side TtjrrclVni 



(lenital opening with more than three disks each side 22 



22. Legs I and II with siiii'ully ringed bristles Neuniunnin 



Legs without such bristles 2;:! 



23. Genital opening at tip of body 24 



Genital opening much I )efi trv t he t ij > 25 



24. Without swimming hairs on legs; fourth joint of palpus without three spurs 



l)elow ; genital area large Fcltrid 



With a few swimming hairs; fourtii joint of j>alpus with three spurs, or papilUe, 

 below ; genital area smaller A tax 



25. Hind epimera witli a i>ointed projection below; j)alpi larger than \e^l. .Najadicola 

 Hind ejiimera without a projection; palpi smaller, and enil in two or three small 



claws; the fourtli joint has two papillae below Fiona 



The genus L!inii<>c/Hins is practically an aquatic Trombidian; the 

 body is of the same shape, and red in color. It can not swim, })ut 



creei)s over the mnd and plants under water. 

 The yoiino- are parasitic on water-skaters 

 (Gerrida^). Our species is very like the 

 European. 



We have three species of Eylah. They 

 are distinguished b}' having- four simple 

 eyes situate close together on a plate near 

 the median line. They are most frequently 

 found in ponds. A larva of this genus has 

 l)een found on mosquitoes. The gen us T/iyns^ 

 of which we have a few species, has no swim- 

 ming hairs on the legs, and beside the lateral 

 eyes there i.s a median eye in front. Several 

 speciesof ArrennniK have l)een described from North America. and doubt- 

 less many more occur. They are often green in color, and have a chiti- 

 nous dorsiun. The dorsum has a circular furrow in the male open behind. 



tiS.— Venter of lebertia. 



