A STUDY IN ANTENNAL VARIATION.* 



By Edith M. Patch. 



PLATES XXIV-XXVII. 



During the summer and fall of 1912 annulation counts of 

 1243 antennae of Schizoneura developing on Ulmus (leaf and 

 bark), and Pyrus and Crataegus (bark) were made by Mr. 

 William C. Woods and the writer of this paper. 



A detailed record of the annular sensoria present on each 

 of joints III, IV, and V of every antenna counted, giving a 

 tabulation of 3729 counts in all, is preserved on file at the 

 Maine Agricultural Experiment Station and a copy of this 

 record will be lent upon request to any one making a par- 

 ticular study of the species concerned. The counts in tabular 

 form are too bulky to be conveniently printed as they stand; 

 and as nearly 100 curves would be necessary to cover the 

 various collections adequately that method of presentation 

 was also rejected for the time though part of the data may be 

 reduced to this form later. 



The drawings of the 90 antennae selected show, however, 

 the most significant ranges of variation and give in themselves 

 a summary sufficient for most purposes. The antennae are 

 all drawn to the same scale with particular reference to the 

 number of annulations present on each of the joints III to V 

 and where of interest also of joint VI; and the length of each 

 joint. No especial attention has been paid to other antennal 

 details and the drawings are not to be considered a study of the 

 terminal joint except in the two respects indicated. In some 

 instances the drawings were made from mounts in which the 

 antenna was curved on the slide and an arbitrary correction 

 of this for the purpose of getting approximately straight draw- 

 ings for plates, gives the peculiar irregularity in contour ap- 

 parent. 



Frequent examples of freak antenna in which two joints 

 were apparently merged were met and some of these are rep- 

 resented by Figs. 32-36 and Fig. 82. 



Appreciative thanks are due to several widely scattered 

 entomologists for their kindness in sending material from 

 different localities, who are, in part, acknowledged in the 

 collection data which follow. 



"Papers from the Maine Agricultural Experiment Station: Entomology No. 62. 



233 



