34 JOHN B. SMITH. 



to fading or flight. There is some difference in the amount of black 

 powdering which affects the relative distinctness of the parts, but 

 nothing else of account. The antennae of the male have the joints 

 well marked and laterally furnished with tufts of moderately long, 

 soft liair. 



Xyliiia grotei Riley. 



1SS2, Riley, Papilio. ii, 102, an var. ante.nnata. 



1887, Grt., Can. Ent., six, 54, Lithophane. 



1893, Smith, Bull. 44, U. S. Nat. Mus., 229, Xi/lina. 

 cinerosa \\ Grt. 



1879, Grt., Bull. U. S. Geol. Surv., v, 202, Lithophane. 



1882. Riley, Papilio, ii, 102, nomen bis lectiim. 

 Head, thorax and ])riniaries dull, dark ashen gray. Head with an admix- 

 ture of white, and with a blackish frontal line. Thorax with the transverse 

 line very obscure or altogether wanting. Thoracic crest low, in very rare 

 instances feebly divided. Vestiture flattened hair mostly. Abdomen a pale 

 mouse gray, without obvious dorsal tufts. Primaries with a slender black line at 

 base, extending to the geminate basal half line, the included costal region paler, 

 but raj-ely contrasting. T. a. line geminate, included space a little paler, defiiiing 

 lines somewhat diffuse, not much darker than the ground color, as a whole a 

 little outwardly oblique, rather regularly outcurved in the interspaces. T. p. 

 line geminate, included space paler, inner portion crenulate, outer even, very 

 little darker than the ground, its course as a whole evenly outcurved over the 

 cell, well drawn in below and with a little outward tooth on the internal vein. 

 S, t. line obscure, pale, broken, preceded by continuous, irregular blackish spots, 

 sometimes marked by a few reddish scales. A series of slightly darker terminal 

 luuules which may be entirely obsolete. Median shade usually traceable, some- 

 times fairly evident, often absent, oblique between the ordinary spots to the 

 lower portion of reuiform, there forming almost a rectangle toward the inner 

 margin. Claviform small, outline diffuse, often obsolete, rarely dark filled. Or- 

 bicular oval, oblique, paler. Suborbicular transversely oval, pale ringed, usually 

 separated from the orbicular. Reniform moderate in size, a little constricted, 

 lower portion somewhat larger than upper and somewhat darker; centre with a 

 brownish shading. Secondaries smoky, with a faint reddish tinge, the fringes 

 paler. Beneath gray, with a reddish tinge, powdery, disc of primaries blackish, 

 secondaries with an exterior line, all with a blackish discal spot. 

 Expands 40-46 mm. = l.GO-1.84 inches. 



if(/ 6.— Canada, south to the District of Columbia, west to Ne- 

 braska, Dakota and Manitoba. 



This is at once the most connnon and widely distributed species 

 of this group. In fresh examples all the ordinary maculation is 

 traceable, and there is no difficulty at all in .separating the species 

 fVom its allies. Spring specimens, especially when flown, lose their 

 characteristic appearance and may become difficult to distinguish 

 from nnimoda. From antennata this species differs obviously by its 



