66 N.S. ENTOMOLOGICAL SOCIETY. 



Sixth Instar. — As with the rusty tussock, the female larvae frequently moulted a 

 fifth time, eleven to thirteen days after the fourth. The head measures 3.2mm. 

 -3.5 mm. in width, shining black in color. There was very little difference in appear- 

 ance or size from those that had only moulted four times, when the two were ready to 

 spin their cocoons. During the last few days of the larval period, all the larvae fed 

 voraceously and grew rapidly. The different sexes were easily distinguishable at this 

 time, the males being condiserably smaller. 



The Male Larva when full grown and ready to spin its cocoon is 25 mm.-28 mm. in 

 length and 3mm.-4mm. in width across the dorsum of the second and third abdominal 

 segments. The two lateral pencils on the first thoracic segment are- 9 mm.-lO mm. in 

 length. The black pencil of hairs on the dorsum of the eighth abdominal segment is 

 9-10 mm. in length. The brushes on the dorsum of the first four abdominal segments 

 vary in color from creamy white to dull black; 3 mm.-3.5mm. in length. All tubercles 

 bear tufts of gray and black hairs except the two on the dorsum of the sixth and seventh 

 abdominal segments. Head black tinged with brown. Prothoracic shield orange to red 

 with two black spots. The long black hairs projecting backward from the ninth abdom- 

 inal segments are 5 mm.-7mm. in length and slightly feathery. 



The Female Larva when full grown and ready to spin its cocoon is 30 mm.-35 

 mm. in length and 5mm.-6mm. in width across the dorsum of the second and third ab- 

 dominal segments. The pencils of black hairs on the first thoracic segment projecting 

 cephalo-laterad are 10 mm.-10.5 mm. in length. The pencil on the dorsum of the eighth 

 abdominal segment is 9.0 mm.-lO mm. in length. The four brushes on the dorsum of 

 the first four abdominal segments are 4.0 mm.-4.5 mm. in length and vary in color in a 

 similar manner to those of the male. The ventral surface also varies in color from yel- 

 low to black. All legs are yellow. The general body color of the female larvae at this 

 stage is not quite so bright as the male. The period between the fourth moult and spin- 

 ning was from eight to fourteen days. (In this experiment one larva started to spin its 

 cocoon three days after the fourth moult). The period between the fifth moult and 

 spinning in the case of a number of females was from nine to eleven days. The last 

 moult always took place after the cocoon was spun, generally from two to three days 

 after spinning commenced. 



THE COCOON. 



The cocoon of the white marked tussock is similar to that of the rusty tussock 

 in appearance, construction and materials employed. The only difference is in size, 

 both sexes being a little larger. The Male Cocoon 20 mm. — 25mm. in length, 8mm.-10 

 mm. wide. The Female Cocoon 30 mm.-35 mm. in length, 10mm. -15mm. wide. 



THE PUPA. 



Both male and female pupae are of a brownish green color at first but later turn 

 to black. The ventral surface is more or less smooth while the dorsum is covered with 

 short scattering whitish hairs and shows very plainly the place where the four tufts 

 or brushes were present on the first four abdominal segments of the larvae. 



The Male Pupa is from 10 mm.-13mm. in length and 4mm.-5mm. in width On 

 the ventral side the eyes, wings and antennae of the future adult can be plainly seen 

 by the outline of the raised portion of the pupal case. The duration of the pupal period 

 of the male was longer than that of the female, being from fifteen to twenty-one days 

 (between the last moult and emergence). 



The Female Pupa is 16 mm.-18 mm. in length and 6 mm.-7mm in width at the 

 widest part. The pupa looks quite oval in shape tapering towards both ends. The po- 

 sition of the eyes, antennae and rudimentary wings are plainly visible on the ventral 



