Watt. — Study of New Zealand Entomology. 263 



The above table gives a total period, exclusive of the egg state, of forty 

 seven days. Another batch under observation made a total of seventy- 

 seven days. Contrast these with Mr. Quail's table, with a total of 248 dars. 

 Here the normal number of five stadiums has been extended into eight 

 on account of the season, on which account also the larvae hybernated 

 in the 6th stadium for 145 days. 



Habits of Larva and Imago. 



The Larva- -On hatching, the young larva makes its first meal off the 

 empty shell. During the first three stadiums it keeps to the underside 

 of the leaves of the food plant, seldom exposing itself on the upper surface, 

 except perhaps during hot sunshine, and eats only the under portion of the 

 leaf, not eating right through and thereby leaving conspicuous signs of 

 its presence. During this time also it utilizes a silken thread in order to 

 reach fresh feeding-grounds on leaves below, or to regain the food plant 

 if forced to drop to the ground for defensive purposes. The slightest dis- 

 turbance during these three periods is generally sufficient to make the larva 

 hurriedly drop from the leaves, and on reaching the ground it will curl 

 itself up. the long hairs of the 2nd thoracic and anal abdominal segments 

 intermingling and so protecting the head. The larvae dislike overcrowd- 

 ing, and on coming into contact with one another will rear up the fore part 

 of the body and strike from side to side, even making attempts as though 

 to bite. In the last two stadiums the habits undergo important changes : 

 the larva will freely expose itself while feeding, and, in fact, feeds almost 

 exclusively on the upper portion of the leaves ; as a rule, they are not so 

 liable to drop from the food plant when disturbed : they do not use the 

 silken thread if so forced to drop ; instead of a life of seclusiveness, they 

 become nomads, often ranging great distances in search of fresh food ; and, 

 lastly, they eat large holes out of the leaves of their food plants, thereby 

 making their presence most apparent. In short, their life after the 3rd 

 stadium changes from one of retirement to one of self-advertisement. Turn 

 now to the table of the' main protective setae and to the paragraph on the 

 development of the larval markings. You will note in the latter paragraph 

 that the markings during the first half of the larval existence are mainlv 

 protective, as distinguished from aggressive, which form they assume during 

 the two latter stadiums. From the table of the main protective setae we 

 find that the number of the hairs increases rapidly during the first three 

 instars. increasing but slightly during the last two : whereas their length 

 increases almost uniformly in each of the five stadiums. Turning now to 

 the period table, one cannot help noticing the similarity in length of time 

 of each of the first three stadiums, and the shortness of their duration as 

 compared with the rest. In the batch mentioned the 1st stadiums occupied 

 only thirteen days out of the total of twenty-nine, and in Mr. Quail's table 

 these three stadiums occupied but twenty days out of a total of 216. The 

 first three stadiums, during which the larva is to a certain extent unpro- 

 tected and therefore leads a seclusive life, are, on that account, greatly 

 shortened, while the protective development proceeds rapidly. It is in the 

 latter two. during which the protective devices, being almost perfect, change 

 but little, that the greatest amount of growth is attained, and in which the 

 caterpillar spends the greatest portion of its larval life-period. It is un- 

 necessary to dwell further on the above fait-. 



I have tried many experiments in order to test the sight and sense of 

 direction of these larvae, but no very definite assertions can vet be made 



