THE CANADIAN ENTOMOLOGIST. 339 



specialized venation. The most plastic characteristic of the venation is 

 the reduction of the submarginal cells from three to two. This occurs by 

 the obliteration of the first or second transverse cubitals or their coal- 

 escence. 



I have examples of the following bees in which the first transverse 

 cubitus is wanting : Sphecodes confertus (faicifer), 4 spec, both wings : 

 S. maiidibu/aris, 2 spec, both wings ; S. antctuiarkc, 2 spec, both 

 wings, 1 spec, one wing ; Augochlora confusa, i spec, one wing ; A/uirena 

 claytonice, i spec, one wing; Nomada Cressonii, 1 spec, both wings ; JV. 

 ob/iterata, 15 spec, both wings, 6 spec, one wing. Examples of the 

 following species have the second transverse cubitus wanting : Sphecodes 

 antenmirice, i spec, one wing; Augochlora con/usa, i spec, one wing : 

 Andrena platyparia, i spec, both wings ; A. so/idagi?iis, j spec, one 

 wing; A. biptinctata, i spec, one wing; A. Forbcsii, 1 spec, one wing; 

 A. claytonice, 3 spec, both wings, i spec, one wing ; Nomada Sayi, i 

 spec, one wing. Of the nine specimens of Sphecodes, all have the first 

 transverse cubitus wanting, one of these having the second obliterated in 

 the other wing. Of the eight specimens of Andrena, all have the second 

 transverse cubitus wanting, one of these having the first obliterated in the 

 other wing. Of twenty-two specimens of Nomada obliterata^ only one has 

 three submarginal cells in both wings. Halictus anomalus and H. 

 lustrans {Hemihaiictus /ustrans, CkW., = Du/ourea /usirans, A^hm.) I 

 regard as anomalous species of Halictus in which the second transverse 

 cubitus is wanting. 



As far as I know there is no bee with three submarginal cells 

 in which the first recurrent nervure enters the first submarginal cell, or is 

 interstitial with the first transverse cubitus. When the first submarginal 

 is long, the second quite short, and the first recurrent nervure enters the 

 first, or is interstitial, the first submarginal cell is composite, the next 

 is the third, and the dividing nervure is the second transverse cubitus. I 

 consider that the first transverse cubitus is regularly wanting in Prosopis, 

 Panurginus and Neopasites. 



When the submarginal cells are of nearly equal length, and the second 

 receives both recurrent nervures (the first recurrent being rarely 

 interstitial, or nearly so), the first cell is normal, the next is composite, 

 and the dividing nervure is the first transverse cubitus. I'he second 

 transverse cubitus is regularly wanting in Parandrena, Biareolina, 



