162 INJURIES TO MARITIME PINE. 



reckoning up all the partial destructions of them, we would be far 

 from accounting for what had happened : some general plague must 

 have fallen upon this innumerable race of devastators, and the 

 following is my conjecture : 



" In the month of May the Chenilles processionaires bury them- 

 selves in the ground, there to be transformed into the chrysalis state ,' 

 but they bury themselves at but little depth, in order that the 

 butterfly may experience no great difficulty in taking its flight. The 

 process of organic metamorphosis which takes place in the chrysalis, 

 requires, as is known, that the insects be protected against too great 

 aridity ; now the months of May and June in that year were 

 remarkable for very intense heat and unbroken drought ; the sandy 

 soil of the pine woods became desiccated to a great depth ; it was 

 broiling hot, and the chrysalises, being unable to develope in that 

 medium, became almost all abortive. Birth was given to few butter- 

 flies ; and thence it followed there were few chenilles. Two circum- 

 stances appear to me to justify fully this explanation : these are, 

 first, in woods which were somewhat colder than others, and on 

 margins adjacent to moist places, in the following year there were 

 found nests in pretty great numbers ; second, since then, two other 

 years, 1848 and 1849, have been marked by an aridity which was, 

 so to speak, exceptional ; and one result of this was, in the winter 

 1849-1850, great distances might be, traversed without finding a 

 single nest. In 1851 they ceased to be so rare, and I remember I 

 prognosticated that this would be the case, in consequence of some 

 rains which fell in June and July, 1850. 



" Thus a drought has sufficed to put an end to disquieting devasta- 

 tions, against which man had no remedy, and to-day (1851), the 

 number of chenilles processionaires is reduced to one of no great 

 magnitude ; they are, moreover, surrounded by so many enemies that 

 they have for a long time ceased to be redoubtable. 



" Apart from drought or other meteorological accident, the chenilles 

 processionaires might have found, as has happened with other species, 

 in their excessive multiplication itself the cause of ruin and mortality. 

 The number might have been so great that food would have failed 

 them before their complete development, and then they would have 

 perished of hunger before transformation." 



Such were the views advanced by M. Perris, Vice-President of the 

 Societe oV Agriculture des Landes, and distinguished as an entomologist 

 who had given special attention to the insects living on the maritime 

 pine. 



