WILLISTON: ON THE GENUS DOLICHOMYIA. 43 



ably true, as Coquillett says, that Dipalta, Stonyx and IsopeittJics are 

 insufficiently distinguishable from Anthrax by the presence of the 

 third submarginal cell, but Coquillett wholly disregards the differ- 

 ences from each other, which are not at all affected by this character. 

 That Dipalta is identical with Diplocampta Schiner seems more 

 probable. 



Coquillett seems to have been totally in error in his conception of 

 the genus Spogosiyluni.. There are three submarginal cells present 

 in the type, as figured and described, but the third submarginal is not 

 formed by the division of the outer submarginal, or, as Coquillett 

 expresses it, by the anterior branch of the third vein having a cross- 

 vein connecting it with the third vein. Here is another of those 

 genera based upon the presence of a third submarginal cell, and 

 which most probably is an inconstant character. It is of interest to 

 note that Schiner considered* Spogostylum and Argyrommba synony- 

 mous. '■^^^\t\x\.tv(\^\.\xc\.^(\^x Argyrojnceba poecihpJioraw. sp. erwei- 

 tert sich der Aderanhang an der Basis der Cubitalgabel bis zur Radi- 

 alader, es sind also, freilich nur auf einem Fliigel, drei Cubitalzellen 

 wie bei Exoprosopa vorhanden, was mich zu der Vermuthung fiihrt, 

 dass Macquart's Gattung Spogostylum mit der Gattung identisch sein 

 diirfte." I have seen the same peculiarity in Argyronurba, and have 

 no more faith in the character here than elsewhere. 



*Rei«e der Novara. Dipt., 12a, note. 



