54 N.S. ENTOMOLOGICAL SOCIETY. 



THE RUSTY TUSSOCK MOTH 



(IVotolophus antlqua) Linn. 



H. G. Payne. 



T 



HE FOLLOWING is the result of careful daily observations of twenty-five 

 specimens of Notolophus antiqua from the time of hatching until death. 



SUMMARY OF LIFE HISTORY. 



The winter is spent in the egg stage, in clusters which are to be found adhering to 

 the old cocoons on the trunks and branches of trees, old leaves, and frequently on the 

 ground and fences. The eggs hatch in the spring, during the end of June, and the first 

 part of July. The larvae become mature and spin their cocoons during a period from 

 about the first to the middle of August, remaining in the pupal stage from seven to 

 seventeen days, the period being longer for the male than the female. Emergence takes 

 place from the middle to the last of August, after which the female remains on the old 

 cocoon where copulation takes place and the eggs are laid. Egg deposition begins very 

 shortly after the female has been fertilized, the eggs being deposited in a mass on the old 

 cocoon where they remain over winter, there being only one generation in Nova Scotia. 



THE EGG. 



The eggs are laid in a flat mass one layer deep upon the cocoon from which the fe- 

 male moth has emerged, the number in a single mass averaging from three to four 

 hundred. They are laid in regular rows and, unlike the eggs of the closely allied species 

 Hemerocampa leucostigma, they have no frothy covering. 



The egg is .92 mm. -.94mm. in diameter, spherical, the top being flattened and de- 

 pressed; around this depressed or sunken area there is a distinct dark ring. The centre 

 of the cap is lightly punctured, the punctures being finer and closer towards the centre, 

 while the remaining surface of the egg is smooth. The shell is thick and brittle. 

 When first deposited the eggs are creamy white but later turn to a dirty gray. 



THE LARVA. 



The larva in emerging from the egg ate through the depressed area, increasing the 

 size of the hole until it was large enough to permit escape. At this time the hole ex- 

 tended almost to the dark ring. After leaving the shell the young larva fed on it for 

 some time and would completely consume it if tender foliage was not close at hand. It 

 then began feeding on the upper surface of the leaf only, and within six days from hatch- 

 ing entire areas were eaten out; finally the whole leaf with the exception of the mid- 

 rib and larger veins was consumed. It was a characteristic of the young larva when 

 disturbed to drop by a silken thread until danger was past when it would draw itself 

 up and resume its feeding. If touched at any time while feeding or at rest, it would 

 curl up in a ball, a habit whicn applies to the larvae in all stages. 



As a rule the larvae passed through a series of five moults but it was not at all un- 

 common for the female larvae to moult six times. In the present experiment, out of 

 the twenty-five larvae reared seventeen were females; of these twelve moulted six 

 times, as will be seen in the accompanying chart of larval periods. The last moult al- 

 ways took place after the cocoon was spun and the cast skin could be quite easily seen 

 if the cocoon was held to the light. 



After the third moult the female larvae fed more extensively and grew more rapidly 

 than the males, thus achieving their greater size. As a rule they stopped feeding several 

 hours before moulting and spun a quantity of silken threads over the surface of the leaf 

 whereon they intended to moult. 



