Dec, 1917 Bulletin of the Brooklyn Entomological Society 111 



tion of the last abdominal segment of the male differs markedly 

 in the two genera. 



Key to the Species of the Genus Ceresa A. and S. Occurring North 



OF Mexico. 



1. Pronotum banded 2. 



Pronotum not banded 3- 



2. Broad pale spot in middle, narrower one near apex of pronotum, 



diceros Say. 

 Apex of pronotum with apical band only albescens Van D. 



3. Suprahumerals reduced to an angle 4- 



Suprahumerals produced in a horn or tubercle 5. 



4. Length of head greater than metopidium measured from line drawn 



through suprahumerals to anterior border of face, femorata Fairm. 

 Length of head less than metopidium measured from line of supra- 

 humerals to anterior border of face uniformis Fairm. 



5. Lobes of last ventral segment of female distinctly and evenly rounded, 



brevicornis Fh. 

 Lobes of last ventral segment of female not distinctly rounded 6. 



6. Base of notch in last ventral segment of female broad 7- 



Base of notch in last ventral segment of female not broad, acute ... 8. 



7. Suprahumerals only slightly curved backward albido-sparsa Stal. 



Suprahumerals quite long, very acute, strongly curved backward and 



slightly upward constans Walk. 



8. Borders of face more or less rounded, clypeus blunt, not at all pro- 



duced, contiguous with sides of cheeks occidentalis Funkh. 



Borders of face more or less straight; clypeus acute and produced, 

 only seldom contiguous with sides of cheeks 9- 



9. Inner margins of lobes of last ventral segment of female not at all 



sinuate 10. 



Inner margins of lobes of last ventral segment of female more or less 

 sinuate H- 



10. Suprahumerals strongly curved backward, long. Contour of cheeks 



rounded brevitylus Van D. 



Suprahumerals short, reduced to a short tubercle brevis Walk. 



11. Venter black basalis Walk. 



Venter yellow or green or brownish 12. 



12. Clypeus prominently produced I3- 



Clypeus somewhat produced but not prominently so I5- 



13. Very narrow, long species militaris n. sp. 



Somewhat stout species I4- 



14. Inner margins of last ventral segment of female sloping. Plates of 



male long palmeri Van D. 



Inner margins of last ventral segment of female steep. Plates of male 

 short and stout borealis Fairm. 



