no. nr.:;. NORTH AMERICAN GEOMETRID MOTHS— QR08SBECK. 361 



Front square, heavily haired but smooth; palpi stout, subascend- 

 ing, projecting beyom I front, as a whole slightly longer than the width 

 of the space between the eyes; tongue well developed; antenna" 

 filiform or dentate, flattened, finely filiate below. Thorax robust, 

 heavily haired above and below, with distinct central crest dorsally. 

 Abdomen rather stout, smooth, in male ending in broad tuft. Tibial 

 epiphysis of anterior legs originating at middle of tibia and extending 

 to or just beyond apex. Posterior tibia not swollen, with two pairs 

 of spurs, without bail- pencil. Fore wings broad, falcate; costa 

 straight or slightly produced on basal third and turning abruptly 

 near apex; outer margin excised between the veins from apex to Cu 2 . 

 Veins R t and R, from cell; R 3 , R 4 , and R. stemmed and forming with 

 R 2 an accessory cell; M t from cell. Hind wings with outer margin 

 excised between all veins, especially from M 3 to Cm. Sc anastomo- 

 sing with R on second sixth; M 2 absent. 



Marmarea Hulst was made a distinct genus on the character of 

 the dentate antenna? of the male of occidentalis. Dvar mistaking 

 giganteus, a species with filiform antennas, for occidentalis made the 

 genus a synonym of Azelina. In truth, occidentalis has dent ale 

 antennae in common with Colorado, but this, in my opinion, can 

 hardly be considered of generic value, especially in view of the fact 

 that occidentalis in habitus and genitalic structure has strong affinities 

 with modestus, a species with filiform antenna 1 , while Colorado has 

 affinities in these same peculiarities with morrisoriatus, also a form 

 with filiform antennas. In other words, aside from antennal struc- 

 ture they differ more from each other than they do from species with 

 simple antennas. For these reasons I have here regarded the genus 

 as identical with Pero. 



The genus Pero comprises a well-defined and distinctive group of 

 insects, and has for its ally the genus Azelina . Gue nee ( = Stenaspilates 

 Packard), as it is now limited by Warren, from which it is distin- 

 guished chiefly by the simple or dentate antennas in the male. The 

 coloring in the genus varies from light gray and light ocherous, 

 through all shades of these to dark umber brown. The primaries 

 are typically divided into three transverse regions, though the partial 

 obsolescence of the inner line frequently gives the appearance of but 

 a single division; or this line may be obscured by shadings of a similar 

 color producing the same effect. The inner or intradiscal line origi- 

 nates on the costa about one-third out from the base, extends ob- 

 liquely outward to the center of the cell, turns inward to the cubital 

 vein, and is thence twice outwardly scalloped to inner margin, the 

 last sweep usually extending considerably inward to the base of the 

 wing. The anterior portion of this line is heaviesl and is always 

 visible to at least the center of the cell; usually it is very conspicuous. 



