NORTH ami:rican hymenoptera. 213 



25 -Dorsuluni witli strong punctures, separaterl on posterior portion ; abdoniinal 

 spots nearly always all widely separated, rarely forming bands on last 

 two segments ; middle segment strongly punctured above (femora in part 



reddish, trochanters black) decemmaculatus. 



Dorsulum closely and rather finely punctured throughout ; abdomen always 

 more or less banded ; middle segment striated above (femora red m one 



case only, in which case the trochanters are also of that cohn-) 26. 



.36.-First dorsal" segment of abdomen with the punctuation mu<-h more distinct 



than on the rem.iining segments ■-'• 



First dorsal segment with the punctuation but little more distinct than on 



28 



the remaining segments 



27.— Ocelli forming a low triangle ; greater part of femora and the tibiae in part, 

 black ; first abdominal segment and the ventrals not spotted ; dorsulum 



very compactly punctured odyneroides. 



Ocelli forming a curved line ; legs red and yellow ; abdomen beneath and 

 on first dorsal segment spotted ; dorsulum posteriorly with the punctures 



less compact imbutus. 



28.— Femora black at extreme base only, the tibire without an internal dark spot ; 

 abdominal markings large and broad, the ventral segments more or less 



maculated Packardii. 



Femora black except apex, the tibiae with a dark spot withm ; abdominal 

 markings rather slender, the ventral segments not maculated. 



chrysarginiis. 

 29.— Head and thorax not densely hirsute; abdomen not maculated ventrally. 

 the first dorsal segment spotted on each side ; pronotum sharply margined 

 or ridged anteriorly ; hind ocelli not placed behind an imaginary line 

 drawn across the vertex from the outer orbit of one eye to the other. 30. 

 Head and thorax with dense, shaggy hair; ventral segments of abdomen 

 2-5 almost entirely yellowish, the first dorsal with a transverse baud ; 

 pronotum convex, not margined anteriorly ; hind ocelli placed behind 

 an imaginarv line drawn across the vertex from the outer orbit of one 



villosu!^. 



eye to the other 



30.— Head and abdomen rather finely punctured ; dorsulum with the punctures 



close and not very coarse ■^^• 



Head and abdomen, particularly the first dorsal segment, rather coarsely 

 punctured ; dorsulum coarsely cribrose (femora more or less reddish). 



riififeniiir. 



31.— Markings yellow; middle segment posteriorly with a yellow spot on each 



side ; tibiaj not spotted internally ; femora above generally with a yellow 



stripe reaching almost to the base bigeminiis. 



Markings whitish yellow ; middle segment not spotted ; tibia:- with a l)lack 



spot within ; basal half of femora usually black dilect-us. 



32.— First joint of flagellum longer than the two following united ; marks on 

 second abdominal segment pointed internally, those on fifth widely 



separated singiilaris. 



First joint of flagellum distinctly shorter than the two following united : 

 marks on second abdominal segment broadest internally, those on fifth 

 aciculatiis. 



forming a baud 



33.— Abdomen not petiolate, more or less sessile 34. 



Abdomen petiolate, the petiole more or less nodose at apex 77. 



TRANS. AM. ENT. SOC. XXII. JUNE. 1895. 



