igOl] ENTOMOLOGICAL NEWS. 69 



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

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

 variability. 



. a. Differences in which the variation is less than 50 per cent, 

 in any one of the three .species. 



13. (f. Yelloiv basal mid-dorsal spot on the seventh abdominal segment : 

 one-half as long as the segment in it, fraternus (two-fifths i cf , three-fifths 



2 (^, two-thirds 2 fj^, three-fourths i fj* = 31%) ; three-fourths as long as 

 the segment in externiis ; one-half as long as the segment in 18 crassus 

 (two-fifths I (^. continued as a narrow line to apex 1 cJ* = 10^). 



14. 9 . Inferior surface of the second femora : blackish with a pale 

 green stripe in 11 fraterttus (no stripe 6 9 =34%) ; black or dark brown 

 in 5 externus (pale green i 9 = 165^^ ) ; pale green in 3 crassus. 



15- C? $• Tenth abdominal segment : with no mid dorsal yellow in 21 

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

 I rf I 9. total 39^c) ; with a mid-dorsal yellow spot almost as long as the 

 segment in 9 externus (half as long i 9 = 10% ) ; with a mid-dorsal yellow 

 line (20 (^'') or rounded spot (3 9) •" crassus. 



16. <^. Seventh abdominal segment : with no apical lateral yellow spot 

 in xoYz fraternus (present in 8>^ (^ = 44 ^<^ ) ; the same present in 10 ex- 

 ternus ; the same present, but very small in i8j^ crassus (absent in i>^ = 



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

 in one or more of the three species. 



17. (^ 9- Ninth abdominal segment with no mid-dorsal yellow spot or 

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

 I (j^ 2 9 1 a small spot in basal sixth i (^ i 9 . an ill-defined streak in basal 

 half I cJ' 6 9 , an ill-defined cloud in middle two-fourths 2 (^, an ill-defined 

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

 segment i cJ, total \2'/,_ ). With a mid-dorsal yellow band as long as the 

 segment and as wide as the spot on 8 in 5 externus (four-fifths as long ^s 

 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 (^ 

 I 9 , three-fourths as long i (^, two-thirds as long 3 cf — total 44^ in which, 

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



18. 9 • ffind margin of the occiput with three successive convexities in its 

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

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



3 9 IH-, Fig- 9 ; the median convexity replaced by a more or less pointed 

 tubercle in 5 9 Ohio, Ind., Figs. 6, 7 ; no median convexity but a con- 

 cavity instead i 9 Ark. — total 53^ ). Very variable in externus ; 2 9 HI-. 



