LYOAENINAK: TIIECLA ACADICA. 901 



form on the Pacific coast from Vancouver's Island to southern California, 

 Nevada and Arizona ; and I have seen in the British Museum specimens 

 from Nicaragua which to all appearance also belong here.* On the eastern 

 side of the continent it has been found in Montana and Dacotah by Mor- 

 rison, Iowa (Parker), Wisconsin "coninKJu" (Hoy), northern Illinois 

 ( Worthington) , Michigan(Mu8. Mich. Univ. ) , London, Ont. (Saunders — 

 to whose indefatigable researches our princi[)al knowledge of the insect is 

 due), Ottawa( Billings), Montreal "very rare" (Lyman), Bethlehem and 

 Albany, N. Y. (Lintner) and Philadelphia (Blake, Edwards). 



In New England it is rather widely distributed, having been found in 

 Montpelier, Vt. (Minot), Milford "very rare" (Whitney) and Nashua, 

 N. H. (Harr. Coll.), Williamstown and Cape Cod, Mass. (Scudder) and 

 Farmington, Conn. (Norton). 



Haunts. The butterfly occurs in wet places where willows abound 

 (Saunders) ; mv specimens were taken about thickets fringing streams. 



Food plant and habits of caterpillar. The larvae feed on dif- 

 ferent species of willow (Salix), eating the leaves from the edge inward. 

 They are very supple in their movements, their body curving like that of 

 a snail, as they pass from one leaf to another or from the upper to the 

 under surface. They move slowly, and if kept in too close confinement 

 are subject to a species of diarrhoea which often proves fatal. At such a 

 time one refuses food, grows pallid and shrunken, and at its worst stands in 

 an arching posture thrusting out and withdrawing the head. When thus 

 stretched the front half of the body becomes flattened and the hinder half 

 swollen while the head is sometimes so far advanced as to disclose a long 

 neck, the mouth sometimes on the ground, sometimes curved over inwards 

 so as almost to touch the prolegs. This is accompanied by muscular con- 

 tractions of various parts of the body and spasmodic movements of the 

 legs and prolegs, the creature meanwhile standing, as it were, on tiptoe. 



Pupation. The day before the first preparation for pupation, the cat- 

 erpillar takes on a decidedly purplish tinge, and, by the time the girth is 

 made, it becomes a purplish roseate, the oblique stripes a little paler and 

 the subdorsal and infrastigmatal lines still paler. In twenty-four hours 

 the body becomes much shorter and thicker, the back quite regularly 

 arched behind the first thoracic segment and the sides regularly rounded. 

 It measures at such a time 11 mm. long, 5.2.5 mm. broad and 4 mm. 

 high. The girth passes considerably forward and crosses the middle of 

 the second thoracic segment. It is about three days after the spinning of 

 the girth that the final change occurs. First, the form of the chrysalis can 

 be detected beneath the larval skin, the separation of the thorax and abdo- 

 men being evident ; then the skin splits and apparently is withdrawn by 

 the shrinkage of the membrane alone, which frequently remains covering 



• 1 do not find these noticed in Godinan ami Salvin's Biolopjia centrali-americana. 



