124 ENTOMOLOGICAL NEWS. [April, 'o6 



The question whether it is really synonymous with Platypeza 

 I am unable to settle at present, not having access to material 

 in typical Platypeza. Snow declared that a somewhat larger 

 size and the ornamentation of the hind tarsi of the male were 

 the only characters to separate the two genera, and he thought 

 them insufficient. The typical Platypezas figured by Snow 

 show in the male the hind tarsus but little modified — less than 

 in the female — nothing at all of the surprising structures 

 shown in his figures of ornatipes and calceata, which I repro- 

 duce on my plate. The question of synonymy I leave in 

 abeyance, rather hoping that further examination of abundant 

 material may show characters applicable to both sexes ; at 

 least we have subgeneric characters in the feet of the male. 



The two species previously known and the one herein de- 

 scribed will be readily separated by the * characters of the hind 

 tarsi of the males, as shown in the plate. I will only add in 

 this connection that otherwise the three species are exceed- 

 ingly close together, insignis being more uniformly yellow on 

 the abdomen than the other two. The female of ornatipes is 

 as yet unknown, while of the other two insignis has a wholly 

 pure yellow abdomen, differing slightly from calceata. The 

 three species form a very compact group, whether of generic 

 or subgeneric rank. 



In regard to the habits of the adults and the function of the 

 tarsal ornaments, little has been observed. In ornatipes, only 

 three specimens are known, one of which was collected on a 

 window — obviously an accidental occurrence. Of insig?iis, the 

 type male was collected hovering in the air in half-shady open 

 woods, about four feet above the ground ; the females were 

 all collected in rather open woods, hovering in the air, most of 

 them over a wet spot in a shady road, which no doubt attracted 

 them, as the weather at the time was intensely dry. It was 

 about four in the afternoon, and no males were flying at the 

 time. Snow noted a few interesting points about the habits 

 of calceata. The flies were "dodging and soaring in the air 



* Secondary sexual characters are very constant in Diptera, whatever may be the case 

 in other animals. I remember hearing Dr. John B. Smith say that he found the same 

 constancy in Lepidoptera. I have long believed that Darwin over-estimated the varia- 

 bility of these characters in general. 



