OF NORTH AMERICA. 161 



ZYGiENID^. 



ZYGaiNiN^;. 



Genus CYDOSIA. Westwood. 



Head moderately large, free from the thorax ; vertex flat ; front very- 

 prominent, conical, projecting between the eyes which are prominent. 

 Palpi short, stout, scaled, porrected, not reaching the front ; tongue 

 moderate. Antennae of moderate length, simple, wide apart at the 

 base, inserted immediately above the eyes. Thorax globose, smooth, 

 finely scaled. Abdomen smooth, short, slightly projecting beyond the 

 hind wings, moderately slender, truncated, tufted. Legs stout, middle 

 pair with one pair, posterior pair with two pairs of spurs. 



Anterior wings long and narrow. Costa straight, apex rounded, 

 outer margin oblique, inner margin parallel with the costa. Median 

 vein four-branched ; 3rd remote from ist and 2nd ; 4th very remote 

 from 3rd, rising near the base of the wing. Subcostal four-branched ; 

 1st and 2nd thrown off near the end of discal area, rather short ; 3rd 

 furcate midway of its length, one branch reaching the costa, tlie 

 other going to the outer margin ; 4th rises on a short stalk, is long 

 and nearly parallel with the costa. 



Secondaries rather broader than the primaries ; costa straight ; apex 

 produced, rounded; apical half of outer margin oblique; balance 

 parallel with the costa ; anal angle distinct. 



This genus is subtropical, the species being of small size. Its colors 

 are metallic, which circumstance assists in determining its true system- 

 atic position. It is loaded down with Lilhosian affinities, and might 

 even at first sight be mistaken for a Tinea. Two species are found in 

 the southern portion of the United States, and others occur in Central 

 America and the West Indies. I have in my collection an undeter- 

 mined insect from Costa Rica, having the characteristic form and 

 metallic green color of this genus, but with short pectinate antennas, 

 which connects Cydosia with the Zygajnid forms having antennae of 

 that structure. The two American species may be distinguished thus : 



Anterior wings wtth many white spots, - - C. nobilitella. 



Anterior wings without white spots, - - - C. aurivitta. 



