Proceedin'cs, 1915. 



NOTES ON LITHOCOLLETIS GAULTHERIELLA WALS. 

 (LEAF-MINER IN GAULTHERIA SHALLON). 



Bv R. Neil Cmrvstal, Assistant Forest Insects, Dcjmimon Division 

 OF Entomology. 



The abundant evidence of the work, of what eventually proved to be 

 the above species, in the leaves of Gaultheria shallon, a shrub which is 

 very plentiful in Stanley Park, and indeed in the Coast region generally, 

 is the basis upon which the following notes are presented. 



Xatiirc of the Injury. — The mine is on the upper side of the leaf, 

 and is irregular in form, as a rule, causing the leaves to appear blotched. 

 Frequently these mines may cover the whole surface, as many as five 

 larva; being found at work in the same leaf. The details of the early 

 life-history of this species have not as yet been studied, the larvae being 

 first examined on June 23rd, at which time their average length was 

 5 mm., the mines being then fairly extensive and the larvae nearly 

 full-grown. 



The first pupae actually found in nature were collected on July i8th, 

 three and one-half weeks later. These changed to adults on July 20th 

 and 21 st, this putting the time of change from larva to pupa between the 

 last week in June and the first and second week in July. The writer is 

 inclined to think that the date of emergence of the adults bred in cap- 

 tivity (July 20th) coincided with their first appearance in. nature, as it 

 was about this time that the empty pupa-cases could be found sticking 

 half-way out of the deserted mines ; and in the sunlit spots of the woods 

 the adults could be seen at rest on the leaves or flying about near by. 



About the time of pupation the leaf becomes puckered up and the 

 pupa is found lying in a silk-lined cell covered over by an opaque silken 

 web, closely attached to the sides of the leaf immediately around it. This 

 web was generally found to be circular in shape. The pupa is thrust 

 through a transverse slit near one end of the cocoon. 



On January 2nd. 191 5, Mr. R. C. Treherne kindly collected material 

 from the Gaultheria in Stanley Park and forwarded it to Ottawa. An 

 examination of this material showed that fresh mines had been started, 

 varying in size and shape, none of them, however, being very large. 

 Larvae in various stages of development, varying in length from i to 

 4 mm., were found in the tunnels. The following statement by Miss 

 Annette F. I'.raun, in her paper " Revision of the Genus Lithocolletis," 

 Trans. Amer. Ent. Soc, Vol. 34, page 321, is worthy of note: "In 

 almost all the species, however, the cocoon is only made in the brood 

 of which the imagoes are to appear in the same summer. In a later 

 brood hibernation takes place in larval state, with one or two excep- 

 tions." This was found to be the case with L. gaultheriella, the !arv;e 

 being in all stages of development, none, howe\cr, being nearly full- 



