NORTH AMERICAN DIPTERA. 89 



XOTES AXD I>E|i$CKII*TIO]VS OF NOKTII A.^EKIC A\ 

 K<».>lltVMI>.E. 



BY D. W. COQUIELETT. 



On pages 34 to 37 of his " Synopsis of the Families and Genera 

 of North American Diptera," Dr. S. W. Williston gives a table of 

 the genera of Bombylidse, remodeled from that of the Baron Osten 

 Sacken, published in " Biologia Centrali-Americana," Part Diptera, 

 pages 75 to 77. As this table does not include all of the genera 

 occurring in this country north of Mexico, 1 have constructed an 

 entirely new table, comprising all of the Bombylid genera so far 

 known to occur in this region. Before i)resenting this table, a few 

 notes on some of the proposed genera may not be out of place here. 



Dipalta, Stomjx and Isopenthes. — These three genera of Osten 

 Sacken are founded upon specimens of Anthrax having three sub- 

 marginal cells in each wing, the anterior branch of the third vein 

 being connected with the second by a cross-vein. The examination 

 of a large series of specimens taken at the same time and place re- 

 veals the fact that the presence or absence of this cross- vein is not a 

 specific character, and therefore cannot be used for the separation 

 of genera. My collection contains specimens of the following spe- 

 cies of Anthrax in which this cross-vein, although absent in the ma- 

 jority of cases, is present in rare instances: Anthrax caprea, A. 

 syrtis, A. ivillidoni, A. Junctura, A. sinuosa and A. nugaior. Except 

 in the possession of this cross-vein, these specimens are indistin- 

 guishable from those in which it is absent. Indeed, Osten Sacken 

 remarks that his ZN-o/)e/i<Aes ^'cBJimc^eana, " apart from the presence 

 of this cross-vein, differs very little from Anthrax sinuosa" ("Biol. 

 Cent.-Am." Diptera, page 129). Not only is the presence of this 

 cross-vein of no importance in the different species of Aiithrax, but 

 this is also true of other genera related to Anthrax. Thus my col- 

 lection contains specimens of the following sj)ecies in which this 

 cross-vein, although normally absent, is present in one or more in- 

 stances : Mancia nana, Argyramoeba. pauper, A. daphne and A. varia ; 

 while specimens of the following species have this cross-vein present 

 in one wing but absent in the other ; Lepidanthraz campestrls, An- 



TEANS. AM. ENT. SOC. XXI. (12) MARCH, 1894. 



