55 



Platypeza flavicornis Loew. 



P. submacula Banks, Journ. N. Y. Ent. Soc, vol. 23, p. 214, 1915. 

 P. mediana Banks, Journ. N. Y. Ent. Soc, vol. 23, p. 215, 1915. 



The typical form is readily separated from the following species 

 by the third section of the fourth vein being noticeably longer 

 than the fourth section, — almost two-thirds in some specimens. 

 However, this difference is often much less and to define the limits 

 of "subequal" becomes quite difficult, especially in the females, 

 but with discretion it can be used to separate the two forms. In 

 the females the gray lateral spots on the abdominal segments are 

 usually much smaller than in P. minorata Banks. I have been 

 unable to use the hind tarsi in defining the species and the an- 

 tennae vary from yellow to dark brown in both. 



In the large series before me of those species in which the males 

 are an opaque velvety black, there is apt to be more or less dis- 

 coloration of the abdomen, either owing to the specimens coming 

 in contact with moisture in the cyanide bottle or by being in- 

 jured during capture, and the fluids of the abdomen spreading 

 over it, gives it a somewhat grayish-black color, and in some cases 

 shining black. Again, we have the grayish spots thus formed 

 apparently disappearing in time and the specimen again assuming 

 a uniform velvety black. This is what has undoubtedly occurred 

 in the case of P. submaculata Banks. In the type the three spots 

 described and figured have almost disappeared, there being only 

 the faintest trace of one, and that has not the original shape or 

 exact position. In P. mediana Banks the abdomen is grayish 

 somewhat shining and the irregularity of the velvety-black spots 

 would also indicate that they were accidental. I have a similar 

 specimen with the venation of P. minorata. A specimen of P. 

 velutina also has as highly polished an abdomen as that of the 

 type of P. nitida Banks. It has undoubtedly been caused by the 

 abdomen being injured. 



This species has been bred from mushrooms (Agaricus cam- 

 pestris) by Professor Roland Thaxter at Belmont, Massachusetts. 

 It has also been collected at Franconia, New Hampshire (Mrs. 

 A. T. Slosson); Brookline, Auburndale, and Chester, Massa- 

 chusetts, August 13-September 24; Riverton, New Jersey, and 

 Delaware Co., Pennsylvania, August 28 and 29 (C. W. Johnson); 

 Colden, Elma, East Aurora and Niagara Falls, New York, August 

 ^-September 20 (M. C. Van Duzee) ; Falls Church, Virginia, 

 August 24-September 24 (N. Banks) ; Ridgeway, Ontario, August 

 12QVI.C. Van Duzee). 



Platypeza minorata Banks. 

 Plate 5, fig. 1. 

 P. minorata Banks, Journ. N. Y. Ent. Soc, vol. 23, p. 214, 1915. 

 P. nitida Banks, Journ. N. Y. Ent. Soc, vol. 23, p. 215, 1915. 



The type of this species is from Falls Church, Virginia. It is 

 closely related to P. flavicornis and can only be separated by the 



