No. 428.] THE METAMORPHOSIS OF SISYRA. 629 
veins, as far out as the point where they cease to be uniform, 
and the ten different forms of tips appended to these branches, 
found in the specimens studied. The branches of R2, R, etc., 
are lettered (a, 4, c, etc., Fig. 18), and the different types of 
tips numbered (1-10, Fig. 18) to correspond with the letters 
and numbers of the table. . The variants and their frequencies 
are shown for each lettered tip in the table; e.g., tip No. 7— 
the most common type— occurs, in the fore wing, four times 
on branch a, sixteen times on branch å, etc. 




FORE WING. | HIND WING. 
LEFT. SYMMETRICAL. | RIGHT. LEFT. SYMMETRICAL. | RIGHT. 
I * 5.45 o 1 B 4 10 1 4534 5 B T 5 9 Io 
a 3 4-4 1 3 2 2 15 3 
b 31 216 4 5 20 
€ ta if or 4 
d 5 19 I 31 3 
e 6. | 2 17 [32 
J I 22 2 4 2i 
s I 24 I LII I3 
A 7 18 14 II 
; eee d uz 4 
H H I 19 6 
k 2 12 9 2 n br4 3 2 
É 9 2:5 4 7 Hj 3 4 
- 9 7.5 4 5 29 
^n II 7 7 2 22 I 
o 4 16 I 4 2314 42 
Ż 4 2I 25 







From a glance at the table and Fig. 18 one sees the 
tendency is toward extensive multiplication of symmetrical 
branches on R2, and that back of R; the branching becomes 
increasingly asymmetrical toward the left, this asymmetry cul- 
minating in Cz:, especially in the hind wing. No variation in 
the cross veins of the hind wing was observed in the twenty- 
five specimens examined, and only a slight variation in those of 
the fore wing. In every case the variations noticed were in 
the disk of the wing, except that in two cases there was a 
Cross vein between the first pair of secondary branches of R2 
