68 THE CANADIAN ENTOMOLOGIST. 



take toll in no small measure from the final outcome. Field mice and 



skunks consider these pupae most delectable diet, and their thoroughness 



is so apparent in the demolished galls, one wonders how any escape their 



keen noses. The writer has drawn attention to this in an early paper, 



when the species was referred to as "necopina" (Can. Ent., Vol. XXX, 



131), how they always select a gall containing a pupa, and never one that 



contained a parasitized Larva. This is easier than might appear, for they 



have but to feel for the exit door to know that a larva has matured and 



pupated therein. When there is no door there will be no pupa, for the 



Hemiteles had the first chance. The mice gnaw a hole half an inch in 



diameter or larger in the side of the gall, sufficient to extract the pupa, 



while the skunks with their greater strength tear a rougher and larger 



opening, and do a noticeable amount of scratching about the root-clusters. 



As very few pupae escape in any locality these animals go over, they 

 become an important factor in the" economy of the species. So far as 

 observed, no others suffer in this manner from these animals, though why 

 the pupae of impecuniosa escape is not easily explained. 



In a final word as to the ontogenetic features displayed in maritima, 

 that most at variance with the congeners is the tuberculate character of 

 the front of the pupa, though the larva shows some individuality from its 

 immediate associates, as, in fact, docs the moth. The supposed great 

 similarity to necopina, which has deceived all, vanishes when the species 

 become properly known. While the tubercle is not continued in the 

 imago, it may be inferred we have to do with a species connecting with 

 Ochria, whose moth possesses an armature of this nature on the head, 

 and which may be needed to force its W2y out of the chamber containing 

 the pupa. With our species there is not this need, and the moth has lost 

 the character, though a trace remains in the chrysalis. 



There is the other alternative, of considering a pupal armature of use 

 in opening a way to the surface through intervening tissues, in those cases 

 where the moth emerges free at the outside of the burrow. Then 

 maritima would be leading up to this specialization of Ochria. But no 

 Papaipema make this effort of wriggling to the outlet, and all make 

 openings to allow of the escape of the moths. Neither the pupa of Ochria 

 nor its action is known to the writer, but the larva of O.flavago reflects a 

 different phylogeny, more in keeping with Gortyna. 



