Robertson — New or Little Known North American Bees. 47 



Parandrena andrenoides (Cr.) Rob. form bicolor, n. f. 



All males I have seen are black. I assume the black female 

 to be normal and propose the form name for the female with 

 red abdomen. Intermediate forms are rather rare. 



Of the four species, Andrena erythrogasira Ashm., A. illi- 

 noensis Rob., A, mariae Rob. and Parandrena andrenoides, 

 the first is the only one in which the abdomen of the female 

 is not commonly, or usually, entirely black. A. erythrogasira 

 and A. mariae are the only ones in which the males show even 

 a trace of red. A specimen of A. sphecodina received from 

 Prof. Cockerell is the only male I have seen with the abdomen 

 quite red. This is probably a synonym of A. mariae. By 

 itself the red color is of no value except as indicating a mere 

 variant form. 



In Trans. Am. Ent. Soc. 24: 150, Prof. Cockerell says : 

 44 Robertson has suggested that P. andrenoides may be 

 a Scrapter, but Dalla Torre places Scrapter as a synonym of 

 Macropis, and certainly andrenoides is not a Macropis" 

 Nevertheless, P. andrenoides may be a Scrapter and also a 

 Macropis in the sense of Dalla Torre. It only follows that 

 his Macropis must be defined to include /Scrapter, just as his 

 Podalirius must be defined to include Entechnia and his 

 Eucera to include Emphor. 



In Bull. Soc. Ent. France, 1897, 63, Vachal discusses the 

 characters of Scrapter and shows the composite character of 

 Macropis D. T. It appears that Scrapter differs from An- 

 drena only, or mainly, in having but two submarginal cells. 

 He says : " De tout ceci il resulte que le chapitre Macropis de 

 M. Dalla Torre doit etre remanie et les especes qu'il contient 

 etre reparties an moins en trois genres, et meme en quatre, 

 s'il resulte de Texamen des types que les especes australiennes 

 de Smith ne peuvent entrer dans aucun desautres." 



Whether Parandrena is a section of Andrena or the same 

 as Scrapter remains to be seen. P. andrenoides and welles- 

 leyana are quite distinct. The males agree in having the 

 angles of the sixth ventral segment reflexed. Andrena 

 crataegi, which is not related, is the only Andrena in which 

 I have found a similar structure. 



