136 ENTOMOLOGICAL NEWS. [April, '07 



situation. It was not common in either locality, and I have not 

 found a specimen in ten years. 



I wish the few remarks above about the habitat of species 

 of this genus might interest collectors in scanning trunks of 

 trees more closely. Not only Scellus, but Medeterus and Neuri- 

 gona, of the Dolichopodidae, are found there, as well as flies 

 of other families. 



Students of secondary sexual characters could not find a 

 more interesting group than Scellus; for lack of space, I have 

 not half described the peculiarities of the male in virago, and 

 all the species have nearly as many male characters. 



TABLE OF SPECIES OF SCELLUS, BASED ON THE MALES. 



1. Third antennal joint elongated, with apical arista .... virago n. sp. 

 Third antennal joint not elongated, with dorsal arista 2. 



2. Hind femora greatly thickened and arcuated, wings wholly blackened. 



exustus Walker. 

 Middle femora arcuated, thickened towards the middle, wings not 



entirely blackened 3. 



Middle and hind femora not arcuated avidus Loew. 



3. Apical half of the wings black, thorax above with snow-white pollen. 



spinimanns Zetterstedt. 

 Not as described 4. 



4. Anal appendages terminating in spoon-shaped, orange-colored en- 



largements monstrosus Osten Sacken. 



Anal appendages not enlarged at tip 5. 



5. Hind femora along the middle with abundant, long white pile . vigil 



Osten Sacken. 

 Hind femora without white pile filiferus Loew. 



Notes on the Habits of Scellus virago Aid. 



By R. W. Doane, Stanford University. 

 The broad salt marshes bordering San Francisco Bay near 

 Stanford University are for the most part covered with the 

 common salt grass (Salicomia ambigula) , but here and there 

 are larger or smaller spots entirely devoid of any vegetation 

 and glistening white with a thin encrustation of salt. These 

 are favorite places with many of the insects that live on the 

 marsh, seeming to be a sort of general rendezvous, where 

 they can bask in the sun, carry on their courtships or build 



