I90l] ENTOMOLOGICAL NEWS. 69 



in which, however, the variability is much greater. These also 

 are arranged, approximately, in the order of from less to greater 

 variability. 



<?. Differences in which the variation is less than 50 per cent. 

 in any one of the three species. 



1 3. -:' . ) 'C//OTI ' basa/ mid-dorsal spot on the seventh abdominal segment : 

 one-half as long as the segment in \$fralcrnus (two-fifths i (j\ three-fifths 

 2 (j\ two-thirds 2 tf\ three fourths i r^ == 31 '/ ) ; three-fourths as long as 

 the segment in e.vternus ; one-half as long as the segment in 18 crass us 

 (two-fifths i fj', continued as a narrow line to apex i tf == io'/r ). 



14. Q. Inferior surface of the second femora : blackish with a pale 

 green stripe in \\ fraternus (no stripe 6 9 =34^ ) ; black or dark brown 

 in 5 e.vternus (pale green i 9 : = i6 2 s''' ) ; pale green in 3 crassus. 



15. $ 9- Tenth abdominal segment : with no mid-dorsal yellow in 21 

 fraternus (trace of a spot 2 ^ 2 9 . a very small spot i $ 8 9 , a large spot 



i rf i 9) total 39 V) ; with a mid-dorsal yellow spot almost as long as the 

 segment in 9 e.vternus (half as long i 9 : = I0 ''')', with a mid-dorsal yellow 

 line (20 rT) or rounded spot (39) i' 1 crassus. 



16. (5\ Seventh abdominal segment : with no apical lateral yellow spot 

 in \oy 2 fraternus (present in 8j <$ =44'^) ; the same present in 10 e.v- 

 ternus; the same present, but very small in iS}4 crassus (absent in ij^ = 



I- 



b. Differences in which the variation is 50 per cent, or more 

 in one or more of the three species. 



17. C? 9- Ninth abdominal segment with no mid-dorsal yellow spot or 

 band in 20 fraternus (with an extremely small isolated basal yellow spot 

 i (^ 2 9 > a small spot in basal sixth i $ i 9 , an ill-defined streak in basal 

 half i ^ 6 9, an ill-defined cloud in middle two-fourths 2 cT, an ill-defined 

 stripe nearly as long as the segment i 9, a distinct band as long as the 

 segment i rp, total 42 '/ ). With a mid-dorsal yellow band as long as the 

 segment and as wide as the spot on 8 in 5 e.vtennts (four-fifths as long as 

 the segment, not reaching the base in i $ i 9. reaching neither base nor 

 apex 2 9, one-half as long as the segment i 9. total 50'^ ). With a mid- 

 dorsal spot as long as the segment in 12 crassus (four-fifths as long 6 $ 



, . three-fourths as long i J\ two-thirds as long 3 rj total 44', in which, 

 moreover, the spot does not reach either base or apex). 



18. . . Hind margin of the ucciput with three successive convexities in its 

 middle and two lateral thirds, the middle convexity angular but not sharply 

 so, in S fraternus (Fig. 8) (these three convexities similar to each other in 

 3 9' 1"-. I'ig- 9 ; the median convexity replaced by a more or less pointed 

 tubercle in 5 * Ohio, Ind., Figs. 6, 7 ; no median convexity but a con- 

 cavity instead i $ Ark. total 53', . Very variable in e.vternus; iQ 111., 



