90 MEMOIRS NATIONAL ACADEMY OF SCIENCES. vol. xii, 



and the others rapidly shortening toward the tip; the distal vestigial pectinations are very 

 slender, longer on the outer side, shorter on the inner side, where they are about one-quarter 

 as long as the basal pectinations, and difficult to detect; extreme tip filiform. 2 . 



Palpi short, stout, with bushy scales at the broad end; third joint not easily distinguishable. 



Thorax without the long subclavate hairs of Dirphia. 



Fore wings very falcate (especially in H. acuta), costal edge very convex toward the apex, 

 inclined to be slightly excavated within ; outer edge quite deeply hollowed out ; inner angle well 

 rounded. Hind wings reaching somewhat beyond the end of the abdomen; apex well rounded; 

 outer edge full, convex, inner edge nearly straight. 



Markings : The wings of both pairs of the same hue and style of markings. No discal spots 

 on either pair of wings; the markings obscure bands and lines, indistinct and diffuse in H. 

 alinda and obsolete in H. acuta. 



The species of Hylesia differ from those of the foregoing genera in the more falcate wings, 

 their smaller size, the shape of the antennae and palpi, the venation, as well as the smaller size 

 of the moths. 



Geographical distribution. — South America; Mexico. 



HYLESIA ALINDA Druce. 



[Plate LXI, figs. 9, 10, is H. cressida Dyar, formerly referred to alinda.] 



Hylesia alinda Druce [Biol. Centr.-Amer., Lep. Het., I, p. 197 (1886), pi. 20, fig. 3]. 

 Hylesia alinda [Holland, Moth Book, p. 90, PI. VIII, fig. 12]. 

 Hylesia alinda Kirby, Syn. Cat. Lep. Het., I, p. [792]. 



Imago. — Two o" . Head, front considerably narrower than in H. acuta, the head and 

 thorax in front dull roseate brick red, the thorax behind and the wings uniformly purplish 

 brown, of nearly the same hue as in H. acuta; thorax with no yellow hairs. 



Fore wings falcate, but not so sharp at the apex as in H. acuta, and the wings of both pairs 

 are banded. Fore wings with a basal line darker than the rest of the wing, but diffuse and 

 obscure. A large elliptical brown discal spot unites with the broad extradiscal band making a 

 Y, the shorter arm of which is made by the discal spot. An irregular faint submarginal shade. 

 Hind wings with two broad diffuse purplish brown bands beyond the middle of the wings, of 

 the same hue as the bands on the anterior pair of wings. 



Under side of the wings a little paler than above; the bands are reproduced, but the discal 

 spot is very obscure and almost atrophied. Abdomen black-brown; no yellow hairs on the 

 upper side, beneath purplish brown. 



Expanse of fore wings, <? , 40 mm. 

 Length of fore wings, 6" , 21 mm. 

 Breadth of fore wings, S , 12 mm. 

 Length of hind wing, <? , 15 mm. 

 Breadth of hind wing, $ , 12 mm. 

 This species lacks the yellow thoracic erect hairs. 



Geographical distribution. — [San Geronimo, Guatemala (Champion); Volcan de Chiriqui, 

 Panama (mus. Staudinger.), Druce, 1. c] Jalapa, Mexico (H. Edwards); Vera Cruz, Mexico 

 (G. Franck). 



[Also said to occur in Arizona, but Dr. Dyar writes that he is in some doubt regarding the 

 identity of the Arizona form. Kirby gives the distribution as "Guatemala, Panama."] 



[Dr. Dyar writes: "I have larvae of three species of Hylesia identified (nigricans Berg., 

 euphemia n. sp., and coinopus n. sp.). Stoll (Supple. Cramer, Pap. Exot., PI. XX) figures two 

 Hylesia larvae, but he assigns them to hirta and bibiana, which are both plainly Lasiocampida?, 

 so they are nameless. He says of the one he calls bibiana 'they live in society on the tree 

 guajaven, and spin in company and almost side by side like the processionea Linn., of Europe.' 

 The habits may vary with the species. Dr. Skinner sent me one (tapabex n. sp.) bred from a 

 'gregarious podlike cocoon."'] 



