SCELLUS. 201 



the fourth and fifth abdominal segments of the male, however, two 

 long, mostly pale-colored tape- or thread-like appendages protrude? 

 which are turned either backward or outward ; their place of in- 

 sertion seems to forbid us to take them for representatives of the 

 ordinary external appendages of the hypopygium ; thus, we are led 

 to regard as such the previously mentioned inferior appendages ; 

 if we do this, then the representatives of the interior appendages 

 will be wanting, unless these same tape- or thread-like appendages 

 are taken for them. If the point 6*f insertion of the tape-like 

 appendages was really at the place where they first appear on the 

 outside, then the question would be solved, as in such a case they 

 could not be considered as appendages of the hypopygium ; that 

 however, this is not the case, and that they rather originate much 

 further inside, and proceed from there upwards between the fourth 

 and fifth abdominal segments, before they reappear on the surface, 

 can be distinctly seen in many specimens ; to ascertain their true 

 place of insertion requires the anatomical examination of fresh 

 specimens, for which I have no opportunity at present. The form 

 and position of the hypopygium and of its appendages in the males 

 of Scellus has so many peculiar features, that it is difficult to 

 arrive at a conclusion about the true meaning of its different parts. 

 The female abdomen consists of five normally developed segments, 

 followed by one segment more, which is shortened, retracted, and of 

 a different color ; the extreme, somewhat opaque tip of the female 

 abdomen is beset with black bristles. The feet are generally 

 bare, middle and hind feet much longer than the fore feet, and, 

 except the thickening of their femora, which belongs to the males 

 of some species, they are more slender than the fore feet ; fore 

 femora thickened towards the basis, on the under side with nume- 

 rous bristles ; fore tibiae on the under side with bristles, elongated 

 at the end into a large tooth, which is still larger in the males 

 than in the females ; the males have, moreover, a strong spine on 

 the inside, not very far from the basis ; the middle tibiae of the 

 male are variously decorated with long curly hairs and stiff bris- 

 tles, while those of the female are plain ; the hind tibiae and the 

 feet in both sexes plain, the joints of the latter of decreasing 

 length ; the empodium distinct. Wings long and narrow ; the 

 posterior transverse vein oblique and close to the margin of the 

 wing ; the third and fourth longitudinal veins converging, the 



