ZooL.-VoL. II.] WHEELER— DOLICHOPODIDM. 3 1 



are their small size, the yellow bristles on the body, the 

 flattening in front of the scutellum, the complete or almost 

 complete absence of bristles on the legs, which are plain in 

 both sexes, the small size of the third antennal joint and its 

 long subapical arista, the absence of the sixth vein in the 

 wing and the long hypopygium with its delicate penis flexed 

 under the abdomen. The description of Aldrich's Xan- 

 thotricha minor from St. Vincent, W. I., is too meager to 

 enable me to distinguish it from my Afhantotimus Willis- 

 toni. I therefore omit it in the following table: — 



1. Femora yellow 2 



Femora metallic green .fraterculus Wheeler. 



2. Venter and sixth abdominal segment yellow. 



cupulifera Aldrich. 

 Venter and sixth abdominal segment not yellow 3 



3. Hypopygium slender, ovipositor-like singul(^ris Aldrich. 



Hypopygium short and thick Wtllistoni Wheeler. 



33. Thrypticus Willistoni Wheeler. 



Plate H, Fig. 49. 



Aphantotimus Willistoni Wheeler, Psyche, July, 1890, p. 376. 



The hypopygium of this species, first described as 

 Afhantothnus Willistoni, is shown in fig. 49. The lamellae 

 are rounded, yellow and fringed with yellow hairs. The 

 long penis seems to be inserted far forward at the posterior 

 end of the venter. 1 have found this species common at 

 Riverside, 111., during June, on the rank undergrowth of 

 damp woods along the Desplaines River. I have also 

 taken it in Wyoming. 



34. Thrypticus fraterculus Wheeler. 



Plate H, Fig. 48. 



Aphantotimus fraterculus Wheeler, Psyche, July, 1890, pp. 2>1^2>11- 



The hypopygium of this species, first described as A-phan 

 totimtis fraterculus, is represented in fig. 48. The lamellae 

 are longer than those of the preceding species, with shorter 

 hairs, and extend backwards. The penis, too, is longer and 

 appears to be inserted on the hypopygium itself. 



