Dec, 1915] Zoocecidia on Species of Hicoria 41 



The writer wishes to express his appreciation of the hospi- 

 tahty of his friend, J. L. King, who, as assistant entomologist 

 for the Ohio Experiment Station, shared his field laboratory 

 during some of the time in which cecidological collecting was 

 being carried on. 



Though the writer has seen (with a few exceptions) the 

 types herewith detailed an amply sufficient number of times 

 to establish them as types, he does not claim infallibility, for 

 the key he has worked out to these types. It is hoped, how^ever, 

 that it, together with the descriptions and illustrations will 

 enable the student of the hickory galls to become better 

 acquainted with the members of the two groups treated. 



Britton and Brown's Illustrated Flora Northern U. S. and 

 Canada, (2nd edition), New York, 1913, has been followed in 

 the matter of plant nomenclature. 



The following two galls whose makers have been named by 

 Felt have probably not been seen by the writer. Felt's 

 descriptions are given. They are not included in the key. 



Caryomyia thompsoni Felt. 



"Globose, thin-walled, long haired, melon-shaped, dia. 2-3 mm." 



See my number 23. 



Caryomyia antennata Felt. 



"Globose, thick-walled, yellowish green or brown. Dia. 4-5 mm." 



This description as far as it goes, would indicate a similarity 

 to C. persicoides Beut. 



Felt, Jour. Econ. Ent. 4:456. 1911. 



Key. 



The itonid group of galls herewith presented can be dis- 

 tinguished with one exception (No. 33) from the very common 

 Phylloxera galls (Aphididae) by the fact that the latter forms 

 which are sufficiently small to be comparable in size to the 

 itonids are intercalated in the leaf blade, i. e. the gall extends 

 more or less prominently from both sides of the leaf. The 

 itonids always give the appearance of an appendicular structure 

 attached to the leaf. 



1. Gall on nut. Caryomyia nucicola. (3) 



1. Gall on leaf. 2. 



2. An apparent elongate enlargement of vein. Cecidomyia cvnipsea (?) (4). 

 2. An inrolled leaf edge. (2). 



2. Galls arising from intervenal tissue between veins or immediately adjoining 

 veins; radially symmetric structures with principal axis more or less 

 perpendicular to leaf blade. 3. 



