42 DIPTERA OF NORTH AMERICA. [PART III. 



with white pollen ; wings hyaline ; all the four species known 

 to me have crossbands, connected near the anterior margin, thus 

 forming an inverted j> an( ^ with a third black band, bordering the 

 apex ; moreover, near the basis of the wing there is a large 

 spot in the shape of a band, or numerous black spots which form 

 a kind of network, not unlike that of some species of Petaloplwra. 

 This difference in the picture of the wings is accompanied by 

 some plastic differences which, if the number of species were 

 larger, could serve for a subdivision in two genera. Those 

 species which have the large spot in the shape of a crossband 

 near the basis of the wings have at the same time the lateral 

 parts of the face very broad, while they are very narrow in the 

 species which have the picture in the shape of a network ; the 

 former have the posterior angle of the anal cell smaller, the latter 

 larger than a right angle, so that in the former, the angle is a 

 large acute one, in the latter, a small obtuse one. One of the 

 species from Australia in my collection, belonging to the second 

 group, is distinguished by the very abnormal structure of the 

 hind tibias of the male. Among the species already published, 

 besides the two described by Macquart, and mentioned above as 

 typical, Ortalis trifasciata Doleschall, from Amboina, may like- 

 wise, perhaps, belong to the genus Celetor. 



Macquart, in the Dipt&res Exoliques, describes as Eniconeura 

 violacea a species distinguished by some peculiar characters, 

 which undoubtedly is to be considered as the type of a distinct 

 genus of Platystomina. The name Eniconeura, or more cor- 

 rectly Heniconeura, cannot be retained, as it has been already 

 used by Macquart himself for a genus of Bombylidse. The genus 

 may be called CLITODOCA. According to that author it inhabits 

 the East Indies ; but this statement may perhaps be erroneous, 

 as I have seen a fly said to be from Guinea, and in which I think 

 I recognize Macquart's species ; there is a slight difference in 

 the picture of the wing, as represented on Macquart's figure, but 

 the agreement of the description is perfect, and seems fully to 

 justify my supposition. By all means the species is a ClUodoca. 

 The characters of ClUodoca may be put down as follows : head 

 large, almost square, with a very short longitudinal diameter ; 

 antennae narrow, descending to the middle of the face; arista 

 with a distinct pubescence; face concave, its lateral portions very 

 narrow ; oral opening very large, broader than long ; clypeus not 



