240 NOTES. 



name Hcnop?! bad been given up; as tbis is contrary to tbe usual 

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



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

 by Tr. Loew, in Bescbr. Europ. Dipt. II, p. 64. For tbe american 

 species, I bave prepared tbe 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 gagathins (Penn\); 



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

 hyaline (lilirjens (VancoivJ 



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

 b. sixth vein prolonged to the margin of tbe 



wing sulphuripeft (New York); 



bb. sixth vein interrupted long before the margin of 



the wing paucus (California). 



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



0. formof^ufi Lw. (Provence), 0. pepo Lw. (Spain), bave the l^rst 



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



from tbe american species in having the body hJacli and yelloio and not 



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



0. perf^x)icillaris Costa unknown to Loew. 



174. Hybos. In the Brit. Mus. H. duplex, triptlcx, purpurciis, 

 stfhjedus Walk, look very nuich like the same species. Tbe two first, 

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

 tbe careless wording of their diagnoses, where pedihus is used in two 

 different senses; once for ?(y/.s, and afterwards for tari^il 



Hyhofi rerersus 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 Sijjiecltes from llijhos , consist in the shape of the bead, 

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

 what broader at the tip; in tbe 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 Hijhos; in tbe 

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



„I take Sy)tcc]i('s in tbis sense, and form alongside of it a new 

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

 loLirtb vein is almost indistinct before tbe discal cell and tbe origin of 

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

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

 origin of tbe third vein is very near that of tbe second. Tbe name 

 Syndyas, which I give to this genus, is intended to allude to tbe 

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

 section of the fourth vein." 



176. Empina. About tbe limits between tbis section and the 

 Hybotina, see in Loew, Fauna Si'idafrica's, p 258. Compare also bis 



