152 PROTECTION OF WOODLANDS. 



proximating as closely as possible to natural conditions, led to 

 very interesting results throwing light on the above-mentioned 

 phenomena. He not only proved that the beetle is endowed 

 with a very long vital period (extending up to two years), but 

 also that the same individual beetles are endowed with the 

 power of re-copulation and repeated ovi-deposition, facts which 

 explain in the simplest manner the simultaneous appearance of 

 recently-developed and of older beetles, as well as of ova, larvae, 

 and chrysalides. 



According to Altum's observations, made throughout many 

 years in the vicinity of Eberswalde, 1 the main time of swarming 

 falls during the warm months of spring, from April till the 

 beginning of June, when the beetles, attracted by the resinous 

 scent, crawl and fly towards the recently cleared falls of conifer- 

 ous crops for the purpose of depositing their ova in the stumps 

 and roots after they have entered in copuld ; reproduction is 

 continued throughout the summer as long as there are suitable 

 breeding-places available for receiving the ova. The eggs are 

 deposited on roots of 0*4 inches or above in diameter that lie on 

 the surface of or below the soil, and when the larvae make their ap- 

 pearance they at first bore only in the cambium, but in develop- 

 ing also attack the sapwood, forming long sinuous larval galleries, 

 trending downwards, and sometimes over three feet in total length. 

 The larvae are yellowish-white, with a large brown head, curved or 

 bent ventrally by contraction on the lower side, and sometimes 

 attain a length of about 0'7 of an inch. By autumn they are 

 fully grown, and then hollow out a pupal chamber for themselves 

 in the sapwood, which they seal up with the bore-dust formed, 

 and in which they rest as larvae till the June of the following 

 year ; there they become transformed into chrysalides in continua- 

 tion of their previous rest in the same chamber, and after a pupal 

 rest of about three weeks the imago makes its appearance, the 

 whole of the metamorphoses occupying about fifteen months, 

 reckoned from the time of ovi-deposition, a period which corre- 

 sponds with the results of Von Oppen's observations. 



But after the beetles, appearing in July, have only partly 

 reproduced themselves, and have only partially deposited their 

 ova, they continue alive till the chief time of swarming comes 



1 About 20 miles from Berlin, where one of the two great Forest Academies of 

 Prussia, (Munden and Neustadt- Eberswalde), is situated, Trans. 



