276 Mr. C. H. T. Townsend on Diptera 



36. Trichopoda formosa^ var. radiata, L\v. 



Two males, San Kafael, July 2 and 4. On flowers of 

 the Cordia sp. 



Length 15 to 17 millim. 



This is the largest known form of Tricliopoda^ the var. 

 radi'ita being even more robust than the typical formosa. 

 The larger one of these specimens is especially robust, with 

 the wing coloration pronounced and the tibial cilia strongly 

 developed. Not only are the hind tibiae ciliate in these 

 forms, but the cilia encroach very largely on the hind femora, 

 the upper and lower edges of the distal third to half being 

 ciliate, as Wiedemann has described. Tiiese apical cilia of 

 the hind femora are more or less developed in other of the 

 larger species of Trichopoda, but in none so strongly as in 

 the present form 7'ac/iata. The wings are rather conspicu- 

 ously yellow in these specimens, in a broad elongate subcostal 

 patch extending from near base to a point halfway between 

 tips of first and second veins. But tlie milky colour is still 

 more conspicuous, radiating from the base of the wing over 

 the yellow and fuscous alike. The abdomen is obscure 

 brownish red with a purplish tinge, the apical segment 

 reddish yellow, which represents more nearly the colour of 

 the abdomen in life. The palpi and bases of femora are 

 reddish yellow. 



T. radiata is doubtless to be considered conspecific with 



formosa. It must be preserved as a good variety on its 



general greater robustness, and the presence of the golden- 



pollinose markings of mesoscutum behind transverse suture, 



which are apparently lacking in the typical formosa, a 



character which Loew failed to point out as differential. The 



somewhat lighter palpi and bases of femora, and more purplish 



abdomen of male, can hardly be used to distinguish it. 



Specimens of Trichopoda vary to a considerable degree. 



Wiedemann's specimens of formosa are described as having 



the thoracic lines white, the outer ones a little golden. In 



the species with conspicuous tibial cilia, these lines are 



normally deep golden yellow. But I have seen them wholly 



white, and even faint. I do not consider the colour of these 



lines of any importance. It is not a sexual, and it cannot be 



considered even a varietal character. In the smaller one of 



the present specimens, the deep golden pollen of mesoscutum 



behind the suture is highly developed, consisting of a pre- 



scutellar transversely-elongate subquadrangular area, with 



lateral edges continued forward in a narrow line on each side 



to suture, while posteriorly it spreads over the basal half of 



