taken on May 10, while it was flying in the sun in a field near the forest. 

 No adults were found in the cages or collected after May 10, which 

 would indicate that in this locality the adults emerge during the last of 

 April and the first of May. Specimens of the fly were sent to Mr. D. "W. 

 Coquillett, who identified them as Gheilosia alaskensis Hunter. 



The last examination of the field breeding cages was made on Octo- 

 ber 10. A number of the resin masses that were caged in October, 1903, 

 still contained larvse. This would indicate th'at the insect lives several 

 years in the larval state. The fact that larvse of various sizes were 



Fig. 4.— Hemloeli bark magftot (Olinlasia alaskensis): m, Resin mass with exit hole, adult fly hav- 

 ing emerged; n, longitudinal section of similar mass, showing wound in inner baric and outer 

 sapwood, pupal chamber and exit hole in outer pitch mass, and original beetle entrance con- 

 necting them : 0, healing wound in inner bark beneath mass like m;. p, healing wound in outer- 

 sapwood beneath mass like m; g, longitudinal section of wound p: i. maggot; s, puparium: (, 

 pupa ; n, adult, male ; », head of female— all about twice natural size ; w. larval head— enlarged 

 about 20 times ; x, antenna— enlarged about 45 times (original), 



found at all times of the year and adults only in the spring strengthens 

 this belief. 



LIFE HISTORY AND HABITS OP THE HEMLOCK BARK MAGGOT. 



The female fly was not observed ovipositing, nor was the egg found, 

 but young larvee were collected from the b"'-^'br"+i'- „„ — :>- y ■' 



