FIELD BOOK OF INSECTS. 



beneath; pronotum, with rare exceptions, distinctly tuber- 

 culate or spined at the sides; head obliquely narrowed 



behind the eyes 3. 



First joint of hind tarsi without the brush-like sole; 

 pronotum usually broadest at the base, its sides never 

 spined or tuberculate; head constricted behind the eyes. . .8. 



3. Antennae scarcely reaching the base of the elytra; 

 pronotum with a sharp spine on each side; elytra with 

 longitudinal raised ridges; black, mottled with brown and 

 gray pubescence; reddish-brown spots on elytra; length, 

 5 to .75 in. Larvas under pine bark, making a nest of 

 chips Khagium lineatiim. 



Antennas longer; elytra not strongly ridged 4. 



4. Eyes globose and prominent; pronotum with a short, 

 acute tubercle on each side 5. 



Eyes not prominent; pronotum angulated or rounded 

 on the sides; length, about .3 in 6. 



5. Elytra uniform reddish-brown, somewhat square-cut 

 at tips. Bores in butternut and beech. Centrodera decolorata. 



Elytra clay-yellow with irregular brown stripes and 

 blotches, the tips rounded; length, .5 in. Bores in hickory. 



Centrodera picta, 



6. Head, pronotum, and under surface black; elytra 

 shining bluish-green; antennae and legs pale brownish- 

 yellow. Breeds in butternut and probably other trees. 



Gaurotes cyanipennis. 

 Not so. Acmaops. For two species see 7. 



7. Stout ; usually dull brownish-yellow ; pronotum with two 

 black spots and each elytron with two longitudinal, 

 black stripes. Western A. bivittata. 



Slender; head, pronotum, elytra, and under surface, 

 yellow except for the black suture, a median stripe, and 

 side margin of each elytron A. dire eta. 



8. Form very slender, strongly tapering behind; last 

 ventral, abdominal segment of male deeply excavated. ... 9. 



Form less slender and less tapering behind; last 

 ventral segment not excavated 12. 



9. Longer than .75 in.; elytra strongly sinuate on the 

 sides; chestnut-brown to black, the elytra with paler 

 areas. Breeds in ash Bellamira scalaris. 



Smaller 10. 



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