I05 



and before the cause of this effect was discovered, it was only by 

 persistently remembering that all the large fir trees were green 

 that the idea could be kept out of the mind. 



Life History. — Unfortunately we were only able to study the 

 insect for about seven days, or from July 22d to 28th, inclusive. 

 During this period we witnessed the pupation of the first brood, 

 the emergence of the imago from this brood and the deposition 

 of the eggs. Whether these eggs will hatch this season or remain 

 as eggs until next spring we do not know. If they do hatch, as 

 is probable, the larvae will be innumerable and produce wide- 

 spread devastation. Neither do we know at what period the but- 

 terflies appeared in the spring, or whether they appeared at all. 

 From analogy there ought to have been a spring brood, of which 

 we found the descendants; but if so, they do not appear to have 

 specially attracted the notice of the scattered settlers, although 

 they observed great numbers last year during the summer. It is 

 therefore evident that, so far as observations in this part of the 

 country are concerned, there is yet much to be learned. All 

 parties, however, who were questioned on the subject agree that 

 the season of 1881 was the first in which the abundance of the 

 pests was such as to cause general comment, the opinion being 

 often expressed that it was not previously known, although this 

 is evidently erroneous. As the winter of 1880-81 was exception- 

 ally severe and peculiar in some of its meteorological phenomena, 

 it becomes of importance to solve the query whether the sudden 

 increase of this species was due to peculiar climatic conditions 

 which destroyed great numbers of its parasitic or other enemies 

 without impairing its own vitality. Certain it is that the silence 

 of the forest was most remarkable, the absence of birds be- 

 ing specially noticeable, while bats were more than rare through- 

 out the whole region traversed by our party, on both sides of the 

 great plateau. 



Habits of the Imago. — The perfect butterfly, when just out of 

 the chrysalis, is one of the most beautiful, but, at the same time, 

 most delicate of its race. It is fragile in the extreme, and soon 

 loses its freshness from its habit of creeping into and between 

 the pine needles in search of the female, or for the purpose of 

 laying its eggs. Great numbers must perish accidentally in high 

 winds ; indeed, dead or damaged ones were plentiful in the dust 

 of the roads. Copulation takes place almost directly after emer- 

 gence, often before the wings are fairly dried ; sometimes the $ 

 being as fresh as the ?, sometimes old and worn. The 

 average duration of life is probably very short, and in this 

 connection it would be interesting to ascertain whether the worn 

 males first seen were relics of the first brood or exceptionally 

 early stragglers of the second. 



■ The Egg. — Examination of the abdomen of a female just 

 after copulation disclosed 49 well-formed eggs. Search for eggs 



