298 AUG. B. GROTE. 



antennae, which are very shortly pectinated in the male M. histrio 

 and simple in the female ; whereas in M. ventilator, of which I be- 

 lieve I have both sexes before me, the pectinations are twice as long 

 in the male as in the new species, while in the female M. ventila- 

 tor they seem very little shorter than in the opposite sex. I have 

 omitted giving the expanse of the male specimen of M. ventilator in 

 my original description. It is 32 m. m. M. histrio expands in both 

 sexes 25 m. m., while some of the specimens, which offer no other 

 difference, are a trifle smaller. 



PTERAETIIOLIX, Grote. 



A very remarkable genus, characterized by a large pellucid impres. 

 sion near the base of the discal cell on the male primary wing, a 

 feature wanting in the opposite sex. An analogous, though not corres- 

 ponding, feature characterizes the genus Heliocheilus. The species is 

 rather small, glistening, pyralidiform in appearance and seems to me 

 related to Anomis. 



The male primary wing shows a large naked impressed spot at the 

 base of the discal cell; underneath, the edges, especially outwardly, 

 are overlapped by the tegument. Qn neither surface are there any 

 hair or scale tufts. The median vein is bent downwardly in a curve 

 at base to make room for the impression, and thus widens here the 

 discal cell. The median nervure is four branched; 2 from the middle 

 of the nervure, thrown off just beyond the downward curve of the 

 nervure; 3, 4 and 5 approximate at base; 4 nearer 5, the latter not 

 independent but springing from the extremity of the nervure on a 

 line with the origin of 4. Cell incompletely closed by a fold. A 

 small subcostal accessory cell from the lower angle of which G is 

 thrown off on to the margin ; 7 and 8 arise together from the outer 

 angle of the cell; 9 out of 8 to apex; 10, 11, 12 are aggregated. 

 Hind wings with two internal veins (1 and la). Median vein three 

 branched; 3 and 4 eminating from one point; 5 entirely independent; 

 cell open ; 6 and 7 arising together on a line with or opposite 2. 



This neuration approaches the pyralidous type, but it does not agree. 

 The accessory cell and the origin of nervule 6 on the primaries, the 

 position of 5 and the presence of but two internal nervules on the 

 secondaries are distinguishing points. The sexual pellucid impression 

 on the primaries differs essentially from that offered by the pyralid 



