392 



PSYCHE. 



[August — October 1S90. 



ANEW CECIDOMVIID INFESTING BOX-ELDER {Neguudo aceroides)} 



BY C. P. GILLETTE, AMES, IOWA. 



Cecidomyia negundinis n. sp. 



Galls. — The galls (G) are produced 

 from terminal buds on all parts 

 of the tree. Each is made up of a num- 

 ber of transformed leaves and peti- 

 oles arranged in pairs in which the two 

 leaves are opposite. They are sub- 

 globular in outline and vary from less 

 than one half of an inch to nearly an 

 inch in diameter. The outer basal por- 

 tion of the gall is formed by an enor- 

 mous enlargfement of the bases of the 



CECIDOMTIA NEGUNIWIS n. sp. 

 Adult female, O, avipositor, E, eggs, G, gall. Fly and eggs 

 greatly enlarged, gall slightly enlarged. Original. 



petioles of two leaves which unite and 

 form a receptacle like the cup of an 

 acorn holding the inner portions of the 

 gall. In the central part of the gall, 

 the leaf blades may be entirelv involved 

 or their tips may be partially expanded. 

 Gall-Jlles. — Females, dry specimens. 

 Eyes large, coal black and coarsely 

 granulated ; a/itennae one-half the 

 length of the insect, 13-jointed, first 

 joint globular, remaining joints cylin- 

 drical, second and third joints con- 

 tracted in the middle, pedicels of joints 

 short, about one-quarter the 

 length of the joints, all of the 

 joints moderately set with hairs 

 the longest of which nearly 

 equals the joints in length. 

 TJiorax very dark brown, 

 opaque, and naked except two 

 rows of long gray hairs in lon- 

 gitudinal grooves running from 

 collar to scutellum and similar 

 hairs at the sides of the thorax ; 

 scutellum of the same color as 

 the mesothorax and with a few 

 long gray hairs. Beneath the 

 wings it is yellowish. Dor- 

 sum dark brown, sides of 

 abdomen and venter light yel- 

 low ; abdomen sparsely set with 

 gray hairs above and below. 

 Ovipositor yellowish brown 

 and in specimens taken while 

 ovipositing, it is exserted one 



Read before the Iowa academy of science, 5 September 1S90. 



