AMERICAN HYMENOPTERA. 189 



wanting in T. claytoiiice, forbesH, hippotes, A. arabis, geranii, illino 

 ensis, platyparia, 0. bipunctata, personata, robertsonii, Pterandrena 

 asteris, krigiana and solidaginU. 



The tibial scopte of Andrena, Pterandrena and Ptilandrena in 

 structure are quite analogous to those of Srjnhalonia, Melissodes and 

 Eateehnia. 



All of the genera mentioned here are vernal,* except Andrena 

 and Pterandrena. Andrena is vernal, with the exception of A. 

 nubecula. Pterandrena is autumal, with the exception of P. laura- 

 cea, krigiana and rudbeckue. 



For an account of oligotropic bees and a list of the food plants of 

 several species of Andreninse, see Botanical Gazette, xxviii, 27-38, 

 215 ; XXX, 130 ; xxxii, 367. 



TRACHAIVIJRKXA fin. nov. (Type Andrena rugosa Rob.). 



FEMALES. 



Fovea below not unusually separated from eye 9. 



Fovea below separated from eye by a more or less cuneate shining space 1. 



1. The space narrower than contiguous portion of fovea 5. 



The space at least as wide as contiguous portion of fovea 2. 



2. Mesonotum bare, almost impunctate ; segment 2 depressed to the base. .nuda. 

 Mesonotum pubescent, rather closely and strongly punctured 3. 



3. Segment 2 depressed three-fourths, or more rugosa. 



Segment 2 depressed about two-thirds; front shining, sparsely, finely punc- 



tu red 4. 



4. Base of abdomen almost impunctate spirseana. 



Base of abdomen closely punctate heraclei. 



5. Abdomen closely punctured, with distinct pubescent fasciae, segment 2 de- 



pressed al)out one-half 8. 



Abdomen more shining, less closely punctured, fascise indistinct, widely inter- 

 rupted, segment 2 depressed more than one-half 6. 



6. Metathorax on each side of enclosure coarsely reticulated and nearly bare ; 



nervures and stigma dark obscura sp. nov. 



Metathorax on each side of enclosure rather finely rugose and closely pubes- 

 cen t • 7. 



7. Pubescence of mesonotum pale; enclosure rounded at apex ; abdomen usually 



more or less red mariee. 



Pubescence fulvous ; enclosure truncate ; abdomen black ; legs red. .hippotes. 



8. Abdomen very closely and evenly punctured, fasciae very di.sti net ; pubescence 



of mesonotum short and feathery quintilis. 



Abdomen less strongly and closely punctured, fasciae less distinct; pubescence 

 of mesonotum long, nearly simple, more fulvous forbesii. 



* Vernal is used here as opposed to autumnal. The species designated as venal 

 complete their flight before July 30th. 



TKANS. AM. ENT. SOC, XXVIII. JUNE, 1902. 



