6 BULLETIX 170, U. S. DEPAKTMEXT OF AGEICULTUEE. 



larva then makes a silk-lined chamber within one of the hollow 

 shoots and. here it pupates. After about three weeks the spiny pupa 

 pushes itself half way out through the dry wall of its chamber and 

 the moth, or adult, issues. 



The full life history of the species in America has not been ascer- 

 tained, because a full year has not elapsed since it was first dis- 

 covered here. While in the main it is the same as in Europe, a very 

 distinct difference has already been noticed, due to the longer and 

 warmer summer and fall in this country. In Europe the young larva 

 attacks only one bud and attains very little growth before it enters 

 the dormant winter season, but in the warmer climate of America 

 the larva eats out two, three, or more buds and attains nearly half 

 of its growth before winter. This, of course, tends to make the 

 species even more injurious here than it is in Europe. 



While it is altogether probable that the species has here only one 

 generation annually, as in Europe, the possibility is not absolutely 

 excluded that on account of the longer season it may eventually de- 

 velop two generations annually like the allied native species. This, 

 of course, would greatly increase its power for injury. 



CHARACTER OF INJURY. 



During the entire spring the infested twigs are very noticeable by 

 reason of the dead and injured buds and young shoots, and the empty 

 pupa skin sticking out of the destroyed shoot is also a familiar and 

 easily noticed sight during the summer months ; but the extent of the 

 injury caused by this insect is only realized later in the season, 

 when the new growth is found to be either quite destroyed or perma- 

 nently injured. 



As may be gathered fromjthe foregoing account of the life history, 

 each one of these insects does very considerable damage, not only by 

 destroying a large number of buds and young shoots but by injuring 

 the adjoining shoots which remain and which normally should sup- 

 plant the destroyed leaders ; thus the trees are permanently disfigured. 

 These injured shoots bend downward and outward and afterwards 

 grow upward again in a curve, in the attempt to continue the normal 

 upward growth of the tree. This results in a characteristic malfor- 

 mation (Pis. IV, V, VI) . so familiar in European pine forests that it 

 has a popular name in each country — as " posthorn " and " waldhorn " 

 in Germany and Holland and " baionnette "in France, while the few 

 examples which have so far occurred in America have suggested the 

 name " Dutch pipe " to those who have noticed it. This injury does 

 straighten out somewhat during the successive years' growth, but 

 never can be fully remedied and will always be noticeable and a seri- 

 ous detriment to the timber (PI. I). Injury of this character is the 

 result even when the species is present in only small numbers, the 



