February, 1«65.] 



197 



NOTES ON THE GALLS OF LAVEBNA DECOBELLA. 

 EY C. G. BAREETT. 



Ou August 24th last, happening to be in one of the favourite 



haunts of Laverna decorella, and having a few minutes to spare, I 



determined to have a search for the larva. 



Tliere was plenty of 



Ejnlohium growing in a 

 sheltered spot ; and, having 

 fortunately hit upon the 

 right place, I almost imme- 

 diately found galls, and in 

 a short time had gathered 

 a large handful. 



I was much disap- 

 pointed, however, ou open- 

 ing some, to find only 

 pupae. Not a single larva 

 was to be found, and in a 

 few more days I should 

 have been still more tantalized by finding only empty pupa skins ; 

 for on the 28th August the first moth emerged, and the rest soon 

 followed it. 



The gall is a swelling in the upright stem of the plant, generally 

 at one of the joints. Doubtless it is caused by the irritation con- 

 sequent upon the larva eating away the pith, as it is quite hollow. At 

 its lower end is a small round hole (probably used by the larva for 

 ejecting the frass), out of which peeps the end of the cocoon, so that 

 enemies are carefully excluded, and the perfect insect finds a soft lining 

 to the place through which it must escape, a great advantage, as the 

 pupa is not extruded. 



The pupa is black, and lies invariably head downwards, the milk- 

 white cocoon filling the interior of the gall. 



This insect i« not confined to one species of Epilohium ; I found 

 the galls equally common on E. montanum and E. palustre, and two or 

 three plants of E. parvijloruni were also attacked. 



For the names of these three plants I am indebted to the kindness 

 of a lady who is pretty well versed in Botany. I cannot pretend to 

 any knowledge of so difficult a group myself 



In E. montanum the galls are generally about the size of a large 

 pea, and frequently occupy several joints of the same stem, but do not 

 otherwise distort the plant or much impede its growth. 



