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.
BioStor
