MEMOIRS OF THE NATIONAL ACADEMY OF SCIEXCES. • 139 



Expanse of wings, S , 30 inni.: length of body, £ , 14 nun. 



This not nncomnioii species difters from all the others in the distinct S-shaped portion of tli(^ 

 fourth or outer line, situated between the costal edge and the cubital vein, the outer curves of 

 the S being tilled in with reddish brown. Also the basal line is not dislocated, both this and the; 

 second line crossing the entire wing and being ])arallel. 



Var. specifica Dyar. Under this name Dr. Dyar brietly mentions a foini of this si)cci<'S 

 ca])riirc(l at JManitou, Colo., May l!, "which differs from the type by its iniicli paler color." 

 Colorado (French). 



E(l<l. — "Of a hemispheric form and dark brown, with a wide glaucous gray riug on the outer 

 margin." (Fitch, p. 275.) 



Lurra. — The following description is drawn u]) from ^Ir. Bridgham's colored drawings of the 

 three last stages and an alcoholic specimen of the mature larva. It occurreil on the pojjlar, 'lul^- 9 

 to 13, those in tiie three last stages occurring at these dates. Other siiecimens were reared by 

 Mr. Bridgham and the nujths olnaiucd from them. (For stage II see Appendix A.) 



Larva in Stage III. — Length, 20 mm. Head as wide as the bo<ly, reddish. The body reddish 

 •on the sides, and green along the back, interrupted by a reddish iiatch on the first and one on the 

 eighth abdominal segments, each of which incloses a median tubercle. The green back incloses 

 three parallel dark green, iiulistinct, interrui)teil lines. There are two greenish tubercles on the 

 side of the body, cue above and the other below the spiracle. 



Stage IV. — Length, 30 mm. The hair is still reddish, but the body has now lost its green 

 shade on the back, which is pale, with three darker parallel dorsal lines. The two median 

 tubercles are now as well developed as in the last stage. The side of the body is pale reddish, 

 with dark lateral tubercles on the thoracic and first abdominal segments, those on the succeeding 

 segments being yellowish, as on the abdominal legs, including the anal pair and suranal plate. 

 The thoracic legs are pale. 



Full-fed liirra. — Length, 30 mm. Head hardly as wide as the body, black, with a y-shaped, 

 inile brown line in front, formed of a median line extending down from the vertex to the ai)ex of the 

 clypeus, and then dividing so as to extend down on each side, ending before reaching the antenna'. 

 The head is liattcned and densely covered with grayish hairs. The three thoracic segments bear 

 each six lateral, rather large, yellowish warts, the lowest one the largest, ea h bearing about six or 

 seven hairs of unecpial length. There is a high median finger-shaped, fleshy nutant black tubercle 

 on the first abdominal segment, bearing numerous short, unequal hairs; it is rather high, finger- 

 shaped, and bent over backward. On the eighth segment is a shorter, smaller, paler one. It is 

 evidently of double origin, its longest diameter being transverse to the body, and somewhat 

 wedge-shaped; the end is somewhat swollen on each side, with a slight valley between the 

 swellings, showing that it was originally formed of two separate tubercles, and this is also 

 suggested by the fact that each swelling bears eight or ten short unerpial hairs. Tlie thoracic legs 

 are black; the abdominal legs are dark, esiiecially toward the planta. 



Colors (described from Bridgham's figure) : Body straw-yellow, with three dorsal, more or less 

 interrupted grayish or pearly ])ale brown lines and a broad lateral stripe, below which the 

 tubercles are yellow ocherous. The suranal plate is flattened, rounded in outline, and hairy, with 

 the surface rather rough and hairy. In my single alcoholic si)ecimen there is no sign of a 

 prothoracic shield or plate. 



Although the imago of/, apiealis is very near that of 7. iiiclusa in markings, the larva is very 

 different, there being no median dorsal tubercle on the first abdominal segment. In the lai'k of 

 these tubercles /. .stru/oaa resembles /. apicali.s. On the other haiui, the larva of I. alboniyma, in 

 respect to the presence of the two dorsal abdominal tubercles, api)roaches that of I. inclusa. 

 These two species, then, as larv;v, belong to the same genus, while the two other species {aplcalis and 

 stri(jo,fa), as respects the larva', difier generically from iiichisa and alboti'ujma, though the moths 

 are congeneric. It is evident that the larva' of «y»'c((//.v and strhioxa are more generalized, since they 

 lack the rather highly specialized d(U'sal tubercles so prominent in the two other species of the 

 genus. If we regarded the moths alone we might erroneously consider that aplcalis and Inclusa were 

 both coeval, whereas apicalh must be a much older, more generalized fi)rm; hence, speculations on 

 the phylogeny of Lejudoptera based on the imagines alone may often be uncertain. 



