2O D. B. CASTEEL AND E. F. PHILLIPS. 



MEASUREMENTS. 



For the measurements taken in this work we have chosen 

 veins and cells which in the bee differ from the typical hymen- 

 opterous wing and which are to a certain extent typical of the 

 bee in their direction and extent. In this choice we have fol- 

 lowed the discussion of the venation of the Hymenoptera of 

 Corrlstock and Needham. 1 The measurements were : (i) Length 

 of vein radius (7?) ; (2) diagonal length of cell radius-four (7? 4 ) ; 

 (3) length of vein media-two (^/,) ; (4) length of medial cross- 

 vein (;) ; (5) ratio between m and M 2 , and (6) number of hooks 

 or hamuli on the hind wing. An attempt was made to 

 measure the angles formed by the union of veins radius-four (7? 4 ) 

 and radius-sector (Rs\ and veins radius-five (7? 5 ) and radius- 

 sector (RsJ, but on account of the difficulty of getting the exact 

 angle at which the veins branch these measurements were dis- 

 continued through fear of inaccuracy. In all cases right wings 



c R 



FIG. i. 



were measured. The measurements were made from camera- 

 lucida sketches, Leitz ocular 2, objective 3 with lower lens re- 

 moved and sketch made at table level, this giving a -magnification 

 of forty-two diameters. In all cases this magnification is retained 

 in the tables. 



The choice of the veins and cells measured perhaps needs 

 some explanation since each one has certain peculiarities in direc- 

 tion or extent. It should be stated, however, that we do not 

 think it makes much difference what veins are chosen for a com- 

 parison of variations in this case since all our observations show 



^omstock, J. H., and Needham, J. G., " The Wings of Insects," Chap. III. 

 (continued), IX., "The Venation of the Wings of Hymenoptera." Amer. Nat., 

 Vol. 32, pp. 413-424, 12 figs., 1898. 



