110 MONTANA EXPERIMENT STATION 



te'nnae may be seen neatly folded down under the head and thorax. 

 By the antennal cases the sex may be determined. 



As the moth emerges a fluid is exuded from the mouth which 

 softens the fibres of the cocoon, thereby making it easier for the deli- 

 cate insect to work its way through the opening. 



As the moth appears immediately after coming out of the 

 cocoon, the wings are but mere watery sacks which hang downward 

 from the body, and the abdomen is distended with fluids. The 

 wings may soon be seen to be elongating and expanding, and in a 

 short time are of full size, but the moth continues to remain quiet 

 until they are dry. Tlie color pattern of the wings is well shown 

 m the photograph. 



The male moth differs from the female in being slightly 

 smaller and in having the antennae much larger and more conspicu- 

 ous. Specimens taken around Bozeman have an expanse of wings of 

 4 to 4^ inches. The photograph is that of a male ; the antennae 

 of the female are much narrower and the abdomen is heavier. 



Eggs were laid in confinement in the insectary on July 5th. 

 The eggs are ellipsoidal, slightly flattened on one end, and with a 

 small flat or depressed spot on the upper side. Length, 2.25 mm., 

 or about i-io of an inch; width, 1.75 mm., or about 1-14 of an inch. 

 The color is a dirty yellowish white. In nature the eggs are laid 

 scattering on the leaves of the plant designed to be the food of the 

 larvae. Our eggs under observation hatched on July 23rd. 



LARVAL DESCRIPTIONS. 



First stage (from hatching to first molt.) Maximum length 

 when ready to molt 9 mm.; width of head 1.25 mtn. Head glossy 

 black or deep brown ; mouth parts whitish with glossy black mark- 

 ings. General color of body smoky brown. Basis of tubercles of 

 the dorsal four longitudinal rows orange yellow, excepting those at 

 the anterior and posterior ends of the body. There are longitudinal 

 rows of glossy black tubercles which are aBout as long as wide, 

 and at the top of each is a cluster of about five stiff bristles, each 

 being a little longer than the tubercle itself. Lower row of tuber- 

 cles shorter and with bristles more numerous. Segment twelve 

 has two tubercles of the dorsal two rows united into one which is 

 broker than the others of the same row. 



