NATURAL HISTORY, TORONTO REGION 



Cecidomyia majalis, Bass. Hosts Quercus rubra, 

 L., Quercus velutina, Lam. A flat, pouch-like gall 

 on the under side of the leaves of the red and black 

 oaks. It is clearly produced by a folding of the 

 leaf, and in this respect resembles the Acarina and 

 Hemipterous types. 



Cecidomyia ocellaris, O.S. Host Acer rubrum, L. 

 The red and yellow concentric rings of colour are a 

 very noticeable feature of this gall. In a slight 

 depression at the centre of these rings the larva 

 rests covered with a viscid fluid secretion. 



Cecidomyia pellex, O.S. Host Fraxinus ameri- 

 cana, L. This gall is formed by a swelling of the 

 blade of a leaflet on each side of the midrib of leaves 

 of the white ash. 



Cecidomyia triticoides, Walsh. Host Salix cor- 

 data, Muhl. A terminal gall produced by a swelling 

 and shortening of the stem of this willow. The lar- 

 val chambers are situated in the buds of the affected 

 twigs. 



Lasioptera impatientifolia, Felt. Host Impatiens 

 biflora, Walt. A monothalamous gall consisting of 

 a spindle-shaped enlargement of the midrib of leaves 

 of the spotted touch-me-not. 



Neolasioptera perfoliata, Felt. Host Eupatoi 

 um perfoliatum, L. A monothalamous gall on bone- 

 set, consisting of a spindle-shaped swelling of 

 stem. 



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