278 



PROOEEDINGfi OF THE XATIOXAL MUSEUM. 



VOL. 49. 



The toiiornl is ;i ciTnin or liglit laii color. Tt rliaii<j;('s tlirou^li liij:lit 

 brown iulo a light brownish violet, and finally mto violet; later the 

 under parts become pruinose. 



Female. — Slightly larger than the male, and especially the abdomen 

 more robust. Wings slightly longer. .Vmong 20 females tabulated 

 the tendency in number of antenodal cells was to a slightly greater 



Figs. 37-38.— Argla. vivida , nymph. 37. Lateral view. 3S. Dorsal \nE'w. 



number than in the male. Two of the 20 had 5 cells in each fore wing 

 and had 4 cells in each hind wing. The averages were, right fore wing 

 4.1, left fore vnng 4.1, right hind wing 3.6, left hind mng 3.4. Legs 

 long, the femora of the anterior pair reaching the second abdominal 

 segment. The best diagnostic character is the shape of the mesos- 

 tigmal laminae, the minute organs on either side of the anterior end of 

 the niiddorsal rarin.v, wliicli uppoiu- to have a form peculiar to the 



