INSECT GAtLS 



Amphibolips confluens, Harris, host Quercus 

 velutina, Lam. Amphibolips inanis, O.S., host Quer- 

 cus rubra, L. These species are the common large 

 " oak apples." While very much alike in external 

 form, the parenchyma zone in the former consists of 

 a dense 'mass of interlocking fibres, while only a com- 

 paratively small number of delicate straight strands 

 constitutes it in the latter. 



Andricus singularis, Bassett. Host Quercus ru- 

 bra, L. In size and external form this gall closely 

 resembles Dryophanta palustris, O.S., but its larval 

 chamber is supported at the centre of the gall by 

 radiating bands of tissue. 



Andricus piger, Bassett, host Quercus velutina, 

 Lam. Andricus petiolicola, Bassett, host, Quercus 

 alba, L. These galls are both produced by the swell- 

 ing of the midrib or petiole, but can be distinguished 

 by means of the different hosts. 



Aulacidea nabali, Brodie. Hosts Prenanthes 

 alba, L., and Prenanthes altissima, L. A large 

 spherical swelling of the base of the stem of two of 

 our rattlesnake-roots, usually just below the ground. 



Aulacidea tumida, Bassett. Host Laciuca cana- 

 densis, L. This species produces an elongated swell- 

 ing of the stem of the wild lettuce, situated near its 

 summit, usually in the panicle. 



Biorhiza forticornis, Walsh. Host Quercus alba, 

 L. The individual gall is almost spherical in shape 

 and has suspended at its centre by radiating fibres 

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