strips, and punching holes for tacks in the tips of the sbips (fig. 2). 

 This was found to be admirably adapted to the work; it was durable, 

 could be readily fitted to any surface, and was easily examined by 

 simply removing the lid. 



The investigations were started 

 too late in the season to secure the 

 pupse or adults, but many larvae in 

 various stages of development were 

 collected and studied, and a num- 

 ber of the infested wounds were 

 covered with the tin cages. 



The most important result of the 

 first season's work was the discovery 

 that the primary cause of the attack 

 and subsequent injury by the bark 

 maggot was the work of the hem- 

 lock barkbeetle {Hylesinus n. sp.) 

 (fig. 3, a)' which was found exca- 

 vating short burrows (fig. 3, 6,c) in 

 the healthy bark, and through it 

 to the surface of the wood, where 

 a small wound was made, causing ^- 

 a slight flow of resin (fig. 3, /). 

 These burrows were evidently made 

 by the beetles for the purpose of 

 obtaining food, and not for the ^' 

 purpose of depositing eggs, since 

 neither eggs nor larvae of the beetle 

 were found, and the burrows were 



soon abandoned. Some of these Piq. 3.-Development ot the black check in west- 

 food burrows were healed over with- ^™ hemlock: », the beetle [ByUsmus n. sp.) 



out further injury to the wood, 

 while others were open and con- 

 tained a small amount of resin. 

 These abandoned galleries, with the 

 resin, formed ideal places for the 

 young bark maggots to begin their 

 work, and were, apparently, utilized 

 in preference to any other wounds. 

 The investigations of 1904 were 

 more successful. Upon the first 



examination of the breeding cages on April 27 one adult male was found. 

 On April 30 a female emerged, and May 8 two males were secured from 

 resin masses placed in cages in the laboratory. Another female was 



that makes the primary injury— natural size ; &, 

 entrance of beetle in outer bark ; c, longitudinal 

 section of u. similar entrance; d, same as &. 

 showing wound in inner bark; e, same, showing 

 wound in outer sapwood ; f, resin exuding from 

 an entrance after beetle has gone ; g, fresh resin 

 mass on outer bark, indicating hemlock bark 

 maggot at work ; ?i, longitudinal section of simi- 

 lar mass, showing position of maggot; i. maggot 

 wound in innerbark; i, same, in outer sapwood; 

 k, resin mass after maggot work is done and 

 the pupa is formed ; I, longitudinal section of 

 similar mass, showing pupa, the wound begin- 

 ning to heal (original). 



iRnl Nn 48- Div. Entom.. TT. S. Dep. Agric, p 20. 



