58 BRITISH GALLS 



resulting from the presence of the larvae of this well-known 

 insect. - 



In all the galls so far alluded to in this chapter the burrow 

 remains open, and provides an easy exit for the imago ; such 

 is the rule with lepidopterous galls. There is an exception to 

 the rule which I may be pardoned for alluding to, though it 

 concerns an African moth, because of its interest. Oecocecis 

 guyonella (Tineidae) deposits its eggs in Limoniastrum guyoni- 

 anum, a plant that is the favourite food of camels on the 

 deserts to the south of Algeria. This plant is frequently 

 covered with sand. The gall completely encapsules the 

 larva, a feature usually seen in dipterous galls. I am not 

 aware of a similar record. This observation was recorded 

 by Gu6n6e many years ago.* The advantage of the sealed 

 cavity is obvious. 



Economic Notes 



There are no very troublesome pests amongst lepidopter- 

 ous gall-causers. Rkyacionia resinella is the chief British 

 example. By destroying the terminal bud of young Scotch 

 Pines it retards the growth of the tree, and where it occurs 

 in abundance, as it does in a few localities in Scotland, it is 

 becoming a serious pest. The only way to keep it in check 

 is to cut off and burn the galls during the second year. 



The larvae of Dioryctia splendidella and Laspyresia cosmo- 

 phorana may affect seriously the Scotch Pine when present 

 in numbers. In these, as in the case of R. resinella, the 

 mouth of the burrow is ma,rked by a lump of resinous 

 exudation. In all there is usually slight hypertrophy of the 

 twig at the attacked part, which feature only, justifies their 

 inclusion in this chapter. 



• Ann. Soc. Ent. France (4), x., 1870. 



