240 NOTES. 



name TT/uops had been given up; as this is contrary to the usual 

 practice in entomology, this family-name cannot well be maintained. 



173. Opsebivs. A more detailed definition of the genus is given 

 by I'r. Loew, in Beschr. Europ. Dipt. II, p. 64. For the american 

 species, I have prepared the following analytical table: 



A. First posterior cell divided in two by a crossvein; 

 B. Anal cell closed ; bases of the third and fourth posterior 

 cells on the same line, or nearly so; 



a. wings brownish gagatinus (Penn*.); 



aa. wings tinged with brownish, base and apex sub- 

 hyaline dilirjens (Vanco iv. >. 



BB. Anal cell open; third posterior cell shorter than the fourth 

 b. sixth vein prolonged to the margin of th^ 



wing sulpliuripes (New York); 



bb. sixth vein interrupted long before the margin of 



the wing pancus (California). 



AA. First posterior cell not divided by a crossvein inflatus (Europe). 



O. -formoKiis Lw. (Provence), 0. pepo Lw. (Spain), have the first 



posterior cell divided by a crossvein; both, as well as inflatus, differ 



from the american species in having the body Mack and ydlmo and not 



uniformly black. (See Loew, 1. c.). 



0. perspicillaris Costa unknown to Loew. 



174. Hybos. In the Brit. Mus. H. duplex, triplex, pnrpureus, 

 siibjectus Walk, look very much like the same species. The two first, 

 as appears from the description, are certainly the same species. Observe 

 the careless wording of their diagnoses, where peclibus is used in two 

 different senses; once for leys, and afterwards for tarsi! 



Hylos reversus is a different species and has the base of the 

 wings hyaline. 



175. Syneches and Syndyas. The passage concerning these genera 

 in Loew, 1. c., runs as follows: ,,The characteristic marks, which 

 distinguish Syneclies from Hylos , consist in the shape of the head, 

 which is flattened in the region of the front; in the palpi being some- 

 what broader at the tip; in the shorter first longitudinal vein; in the 

 second vein taking its origin nearer the root of the wing, and ending 

 more steeply in its margin, than in the true species of Hybos; in the 

 somewhat shorter anal cell and in the usually spotted wings." 



,,I take Si/ncclics in this sense, and form alongside of it a new 

 genus, based on some species of Hybos from the Cape, in which the 

 fourth vein is almost indistinct before the discal cell and the origin of 

 the second vein is still more distant from the base of the wing, than in 

 those european species, which remain in the genus Hybos, so that the 

 origin of the third vein is very near that of the second. The name 

 Syndyas, which I give to this genus, -is intended to allude to the 

 coalescence of the two cells, produced by the indistinctness of the first 

 section of the fourth vein." 



176. Empina. About the limits between this section and the 

 ITybotina, see in Loew, Fauna Slulafrica's, p. 258. Compare also his 



