CLASSIFICATION OF THE BEKS. 91 



Abdomen black aud rufous, almost bare; antennae filiform, in % long: 

 mentuin and tongue long, slender; tibiae dilated at lower apical angle. 



Trichchosftoma Sauss. 

 First cubital cell, along the cubitus, shorter than the third ; stigma well devel- 

 oped ; transverse median nervure straight, interstitial with the basal 

 nervure ; scutellum spined ; mandibles tridentate; maxillary palpi 

 6-jointed. 

 Abdomen very smooth, shining; head and thorax clothed with fulvous 

 hairs; labial palpi 4-joiuted, the first joint about as long as joints 2-4 

 uuited Mellitidea Guerin. 



2. Abdomen normal, not petiolate-clavate 3. 



Abdomen petiolate-clavate; second cubital cell half the length of the third. 



slightly narrowed above; scape of antennae two-thirds the length of 

 the flagellum, the latter subclavate ; maxillary palpi 6-jointed, the 

 three basal joints short, stout, clavate, joints 4-6 slender, slightly 

 thickened towards apex ; labial palpi 4-jointed, the first subclavate, as 

 long as 2 3 united, the two latter short, stout and clavate, the last 

 joint slender, filiform Cory n lira Spinola. 



3. Third cubital cell receiving only one recurrent nervure — the second, the first 



recurrent received by the second cubital cell beyond its middle, or 

 before the first transverse cubitus (or very exceptionally interstitial 



with this nervure) 4. 



Third cubital cell receiving both recurrent nervures, or the first recurrent is 

 interstitial with the second transverse cubitus; rarely is the second 

 recurrent interstitial with the third transverse cubitus; maxillary 

 palpi 6-joiuted ; labial palpi 4-jointed. 



Tongue elongate, lanceolate, the paraglossae long; first joint of labial palpi 

 longer than 2-3 united, the second a little shorter than the third, the 

 third obconical, the last slender, cylindrical : species metallic-blue, 

 blue-green to green Augoclilora Smith = OxystogJossa Sm. 



Tongue short, triangular, the paraglossae not long; first joint of labial palpi 

 about as long as 2-3 united ; first recurrent nervure interstitial with 

 the second transverse cubitus ; non-metallic species, or at most aeneous 

 on the head and thorax; clypeus in % anteriorly always margined 

 with yellow Parasphecodes Smith. 



4. First cubital cell, along the cubitus, as long or somewhat longer than the 



second and third united, the second quadrate, not or only slightly 

 longer than wide, or much wider (higher) than long, and often con- 

 siderably narrowed above 5. 



First cubital cell, along the cubitus, not longer than the second and third 

 united, usually distinctly shorter, the second quadrate, not wider 

 than long. 

 Head and thorax metallic, green, blue or blue-green : abdomen in 9 metallic, 

 black or yellow, in % usually yellow, with black hands, the hind 

 femora in this sex being much swollen, and most frequently with a 

 subapical tooth beneath Agapostemon Smith. 



5. Second recurrent nervure not interstitial with the third transverse cubitus, 



the second cubital cell not longer than wide, usually wider (or higher) 

 than long ; scutellum normal, tongue short, triangular or subtriangular, 

 or in outline cone shaped 6". 



TRANS. AM. ENT. SOC. XXVI. JUNE. 1899. 



