MEMOlItS OF THE NATIONAL ACADEMY OF SCIENCES. 129 



I am inclined to agree with Mr. Dj'ar that this is a variety of I. (qricalis. I am unable, 

 however, to see any important difference between I. ajncalis, var. iiicarvrnda, and alethc Xenm. 

 and Dyar, though 1 leave it as a synonym of brucei, as Mr. Beutenmiiller suggests, Dyar agreeing 

 with his view. 



The following account of the preparatory stages of TcJtthi/ura bifiria Hy. Edw., by Dr. Harrison 

 C Dyar, is copied from the Entomological News, 1892, ]). .J: 



Eg;/. — Hemispberical or sliglitly conoidal, the base flat, but louuded at its edges ; smooth under a lens, but under 

 the microscope covered with numerous, crowded, shallow depressions, which form by their edges narrow, rouuileilly. 

 hexagonal reticulations. The color is dark gray before the egg hatclies. Diameter, 0.7 mm. 



First stage. — Head shining black, laljrum pale; width, 0.3.5 mm. Body slightly flattened, whitish; cervical shield 

 black; a few pale hairs; joints .5 and 12 are slightly enlarged dorsally ; the lateral region .and joints 5, 7, and 12 

 dorsally are wine red. Thoracic feet large, pale; the abdominal normal, all used in walking. Length, 2.5 mm. The 

 larva hatches by eating a round hole in the vertex of the egg, leaving the rest of the sliell untouched. It lives, 

 singly, in .a shelter constructed by spinning two or more leaves together. 



Second stage. — Head black and shining, the central suture deep; width, 0.(55 nnu. Body flattened, pale whitish 

 yellow, with narrow triplicate dorsal, and very broad lateral bands of dull wine color, as are also the humps on joints 

 5 and 12. Cervical shield and anal plate black; venter dull greenisli ; legs black. 



Third stage. — Head flat in front, slightly bilobed, brownish black, but paler centrally around the clypens; a few 

 dark hairs; width, 1.4 mm. Body pale yellow; joints 5 and 12, a triple dorsal line, broad lateral and confused triple 

 subventr.al lines all dark brown. Cervical shield and anal plate blackish; scattered pale hairs arise from smooth, 

 low, round tubercles, concolorons with the markings. 



Fourth stage. — Head pale brown, shaded with black in front; jaws and ocelli black; a white shade on each side 

 of the clypens; width, 2.6 mm. Body as before, but the lateral band is faintly divided by a double yellowish line, and 

 joint 13 is nearly all yellowish. The round, smooth, piliferous tubercles are distinctly yellow in the yellow markings. 

 Cervical shield small, bisected, pale brown ; anal plate not distinguishable. Hair whitish, both from body and heiid. 

 As the stage advances the colors become finite pale, and the .appe.ariince is nuich changed; humps on joints 5 and 12 

 very slight, dark jiurplo. (iround color whitish gray, becoming pale purple, a tripliiate dark purple dorsal line, the 

 central one most distinct, the others broader and diffuse. All these lines are more or less broken into mottlings. A 

 similar stigmatal line with some purple mottlings subventrally ; venter paler; spiracles black. The piliferous 

 tubercles are normal in arrangement, much as the warts in Halesidotu; row (4) sm.all, posteriorly to the spiracles, row 

 (7) apiiarently absent. The head is held out flat, as in Ghiphinin. 



C'oeoim. — Composed of several leaves spun together and lined with threads. 



Pupa. — Xearly cylindrical, flattened a little ventrallj', gradually tapering posteriorly, but of nearly even width, 

 •no part enlarged; last abdominal segments rounded, cremaster long and slender, terminating in a knob 'that, under 

 the microscope, is seen to consist of a row of radiating, strongly recurved hooks, which hold flrmly to the silk of the 

 ■cocoon. Color dark red-brown, the thorax and cases nearly black. Length, 11 mm. ; width, 3.5 mm. 



Food i)lant. — Willow (.So^jj). 



Larva' from Yosemite Valley, California. These larva; had but four stages, and there are two broods in a year. 



Irhthi/iira bifiria, as well as /. brucei Hy. Edw., must come very near /. ran Fitch, if they are not merely Western 

 forms of it, but the larva of /. ran is still unknown, so that it is impossible to compare the early stages. 



We now return to the normal /. apicalis. 



Cocoon. — The cocoon which I have is more completely formed tlian that of I. inelii.<f(t, the 

 ■surface iie.xt the leaves being a continuous firm web, more cocoon-like. It is tent-like and spun 

 between two leaves, as in /. inclitsn. It measures 22 by 15 mm. 



Pupa. — Not so full, rounded, and blunt at the end as in that of I. iuchtsa. Abdominal 

 segments with scattered coarse punctures, and the surface is dnll, not so .shining as in I. inclu.sa. 

 Cremaster slenderer than in I. inclma, the two dorsally curved hooks not so broad and thick as 

 in I. tnclusa and about half as large. Length, 16 mm. 



Babif.s. — In general the same as those of /. inchi.m, the moth laying its eggs in northern 

 New England probably late in June and in July, the larv;T occnrring throughout August. In Mdes 

 City, Mont., the eggs are stated by Mr. Wiley to have been laid on the willow as early as May 24. 

 Whether it is double brooded remains to be seen. It occurred in Kansas May 21. (Bruner). 



Food plant. — The normal New England form of apicaltfi feeds on the aspen, while "the pale 

 western form asforicf^^ in Montana feeds on the willow. 



Gcogrophical (lisfribiition. — The species with its varieties range from New England, including 

 the colder jwrtions, as Franconia, N. H., to the Pacific Coast. It is to be looked lor throughout 

 the greater part of the "cold temperate subregion of Allen, or the boreal (Canadian) province 

 ■of authors from lower Canada (Quebec Province) westward to Alaska." It also spreads in its 

 varieties [ornatn, bifirut, and asfori(f) through the Appalachian and Caini)estrian subi^rovinces, 

 iu(;luding Montana, Washington, and California. Var. indentata, New Jersey, Pennsylvania, 

 S. Mis. 50 9 



