No. 1746. 



I XFAY AUrilll'dl) FKOU VIRGINIA- /.'l//,'0/M 



305 



Table of measurements. 



Number 

 segments in 

 primary 

 ffagellum 

 of first 

 antenna. 



Number 

 segments in 

 flagellum 

 of second 

 antenna. 



60 



4 

 4 

 19 

 17 

 21 

 21 

 23 

 22 

 23 

 24 

 26 



4 

 4 

 19 

 18 

 21 

 21 

 22 

 22 

 23 

 24 

 26 



so 



9 

 10 

 10 

 10 

 10 

 10 



27 



27 



10 

 9 



11 



10 



11 



II 



Telson. 



Qi 



_.« 



o *^ 



SO 



.a a 



0. 533 

 .52 

 .52 



.58 



03 SO 



- 



So 



o .. 



Sex. 



1.00 0.77 



. 954 . 795 



.77 .82 



.SO 77 



.676 



.78 

 . 72:: 

 .660 

 6S5 

 .634 



63 



. 63 

 .606 



756 



.7112 



.76 

 .76 

 .843 



.82 

 .77 

 .66 



.81 

 .8 



Young. 

 ...do. . . 

 Male . 

 do. . . 

 Female 

 Male. .. 

 Female 

 ...do... 

 ...do. . . 

 . ..do. . . 

 ...do... 

 ...do... 

 ...do... 

 ...do... 

 .. do... 

 ...do... 

 ...do... 



do. 



42 



N.X 



Dale. 



Mar. 16,1909 

 do 



do 



do 



do 



do 



....do 



....do 



....do 



do 



....do 



...do 



... do 



....do 



....do 



....do 



do 



do 



Locality. 



Ashland, Virginia. 

 Do. 

 Do. 

 Do. 

 Do, 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 



e 



o 



e 



a 

 >~ 



3 



6q 



Auburn, N e w 



York. 



Do. 

 Ii haca, New York. 



Do. 

 Ashland. Virginia. 

 Ithaca, New York. 



Do. 

 Ashland, Virginia. 



Do. 



Do. 

 Ithaca, New York. 

 Ashland, Virginia. 

 Mel, can Bog, New 

 York. 



a Exclusive of the antennae. 



The pond where this species lived in such great abundance was 

 roughly .'! acres in area, fed by springs within the pond itself and 

 by a small brook at one end. Fish were abundant and from an 

 examination of stomachs of large-mouthed bass (Micropterus sal- 

 moides), common sunfish (Lepomis gibbosus), and calico bass (Pomoxis 

 sparoides) it was found that they helped themselves liberally to 

 amphipods. Especially was this the case with the smaller sunfishes 

 and calico bass, 1 to 3 inches long, a few of which were able to pene- 

 trate the thick masses of sphagnum where amphipods were exceed- 

 ingly numerous. This great fringe of vegetation about the pond, 

 however, furnished a shelter which prevented at all seasons any 

 very great destruction of amphipods by predatory animals, and this, 

 together with the rather large reproductive capacity of the species in 

 question, was sufficient reason for their great abundance. 



Proc.N.M.vol.38— 10 20 



