ODYNERUS. 242 



exclusively American. The 0. bid ens in particular, with its great 

 size, its black-violet wings, its white ornaments, forming large 

 spots, its smooth body, is a type of which the form has no simi- 

 larity either in Europe or elsewhere, while it recalls other 

 species peculiar to North America (Munobia uncinata, Ancislro- 

 cerus 4-sectus). 



The species which form the Division Odynerus occupy in 

 America principally the northern temperate zone. They appear 

 to be yet more numerous in North America than in Europe. 



Table to assist the determination of the species of Division Odynerus. 



Nota. — Compare 0. Crypticus (No. 95), which could not be introduced 

 into this table, not being sufficiently well known ; and at the end of the 

 genus, the list of species incertoz sedis. 



1. Second abdominal segment having a particular form. 



2. Second abdominal segment deformed. 



3. Swollen posteriorly, forming two gibbosities, its margin very 

 deeply canaliculate and much reilexed. 110. cluniculus. 



3, 3. Without strong gibbosities ; the margin only strongly canalicu- 



late. 111. Morelii. 



2,2. Second abd. segment produced in the middle, forming a sharp 

 angle or tooth. productus. 1 



1, 1. Second abd. segment not deformed, normal, not swollen. 

 2. Wings black or fuscous, with violet iridescence. 



3. Ornaments of the body white or luteous. 



4. Metathorax black, 2d segment margined with luteous. 



101. Megazra. 



4, 4. Metathorax maculate with luteous ; 2d segment not margined 



with lutecus. 90. bidens. 



3,3. Ornaments of the body yellow or rufous. 



4. Metathorax angulate. 



5. First abd. segment sharply truncate at base. 



82. Hidalgi, var. 



5, 5. First abd. segment not so sharply truncate, more rounded. 



84. f dorsalis. 2 

 93. ^ annectens. 

 4, 4. Metathorax rounded ; insect velutinous. 109. Romandinus. 

 2,2. Wings subhyaline or clouded or ferruginous. 



3. Body much adorned with rufous; prothorax often rufous. 



4. Metathorax not forming on each side a lateral dentiform angle. 



1 Compare at the end of Genus Odynerus, the species incertoz sedis. 



2 Compare also 0. Boscii and arvensis, sometimes with rather obscure 

 wings. 



