234 REPORT OF THE COMMISSTONEE OF AGRICULTURE. 



were seldom found nyion a larger limb tliaii tlie one represented in tlie 

 plate. 



A longitudinal section through one of these lumps showed a channel 

 of greater or less size leading directly to the heart of tlie twig, and ex- 

 tending along toward its base for a distance of from 25'""' to 50""" (1 to 

 2 inches). In this buiTOw "^as found a rather stout, yellowish-brown 

 larva, apparently nearly full grown, and measuring about lO"'*" (.39 

 inch) in length. In other burrows the short, stout, brown pupae were 

 fountl. Tliey were quite active, and retreated to the bottom of the mine 

 when the resin was cut into. A ring of strong spines surrounded the 

 posterior border of each segment, and enabled them to move about in 

 the mine with considerable rapidity. From other lumps the empty pupa 

 skin was protruding for half its length, the pupa having worked itself 

 to that i)osition before giving forth the moth. 



Some of the burrows examined extended in both directions from the 

 point of entrance. Occasionally also the twig at the i)oint vrhere thp 

 resin exuded was completely girdled, and in other cases eaten out to 

 Buch an extent that a very slight force would suthce to break it off. The 

 larvae were in some cases found with their heads at the mouth of the 

 burrow, but in the majority of instances the opposite was the case. 



The moth which issues from the burrows is quite small and soberly 

 colored. In the figure it is represented natural size; the darker shades 

 are dark rust-color, and the lighter light gray. It belongs to the family 

 Tortricidae, the larvae of which are usually leaf-rollers. 



From what we have been able to learn, we conclude that tliere are 

 two broods of this insect in a year, and that the second brood hiber- 

 nates in the larva state. May 25 burrows were found from which the 

 moths had already issued. In the breeding cages at Washington the 

 moths issued until June 20, when the last one made its exit. August 

 23, larvae were received which were nearly full grown, and were pre- 

 sumably of the second brood. In the following January nearly all the 

 larvae found were only about half grown; none were more than two- 

 thirds grown. 



At the ap]5roach of winter the larvae i)repare their burrows for 

 hibernation by lining them with delicate layers of white silk, which 

 often form tubes closed at the lower end. The larva remains through 

 the winter with its head at the posterior end of the mine. Before the 

 change to the chrysalis state, however, this position is reversed and 

 the head is towards the opening. 



Wherever a twig is pierced and bored by one of these larvae tlie 

 leaves begin to turn yellowish and the twig often dies. In many cases, 

 how^ever, more than one of the larvae are to be found in a single twig, 

 and this of course more certainly insures its death. It seems probable 

 that the principal damage done is the disfiguring of the shai)e of the tree 

 by the destruction of terminal shoots.* 



The moths bred from the burrows were submitted to Professor Fer- 

 nald, who decided that they represented a new specie, sprobably belong- 

 ing to the genus Eetinia. This species he described in the Canadian 

 Entomologist, vol. xi, p. 157. We quote Professor Fernald's description 



* The resin exuding from the bnvrows of tlie Eetinia is sometimes inhabited by dip- 

 terous larvae which correspoud quite perfectly with Osten Sacken's rather incomplete 

 de!5cription of Cecidomyia 2>ini-ino2ns, a species which ho described from larvae found 

 in resiuoua cocoons on the leaves of J'imis inops in the vicinity of Washington, and 

 the adult of which he was unable to rear. The occurrence of these larvae in this 

 exuding resin i)roduced by lietinia would seem to argue that they are not normally 

 injurious, and that the eggs are only laid in pitch exuding from some prior injury. 

 Wd havd not yet bred the adult of this insect. 



