130 
'Tings transparent; nerves at the base and inner portion yellowish- 
white, of the other portions black. Legs bright vermillion red. Pos¬ 
terior femora have a row of black dots along the upper and lower 
iw rgins of the disk and one through the middle; spines of posterior 
tibiae yellow, tipped wdth black. Each segment of the abdomen has 
a ring of dusky dots on its posterior margin. 
Male .—Much smaller. Sub-anal plate prolonged, deeply notched at 
the apex; cerci very broad, straight and truncate at the apex. 
Dimensions .—^—Length of body, 2 inches; elytra, 2.1 inches; pos¬ 
terior femora, 1.15 inches; posterior tibiae, 1.05 inches, m —Length 
of body, L7 inches; elytra, 1.05 inches; posterior femora, 1 inch; 
posterior tibiae 0.9 inch. 
, These dimensions are only intended to express the average, but 
there is less variation in this than in many other species in this 
respect. 
Var. ambignum .—Very similar in size, markings, and carvings to 
americanum from which it differs chiefly and almost exclusively in 
the general color and time of appearance; being yellow or brownish- 
ydlow, where the other is reddish-browm or vermillion. It is also 
scmewhat more robust and appears much e&’iier in the season. 
This species is found only in the southern half of the State. The 
red variety is somewhat common and occasionally quite abundant in 
limited localities. The yellow variety as.a general rule is rarely met 
w’ith and appears to be a more southern form of the species, wdiich 
in this respect corresponds exactly wdth its congenor A. peregrinum 
l 
TETTIGLNJi. (See Fig. 11). 
\ 
The descriptions of the species of this group are omitted for the 
present because of the uncertainty as to what are true specific charac¬ 
ter.sties. It is my intention as soon as I have had an opportunity of 
examining sufficient material and arrive at a satisfactory conclusion as 
to wdiat are really species and what varieties, to describe such as are 
found in Illinois. 
