METHOD FOR DETERMINING THE SPECIES. 9 



and a more or less concave hind margin. An examination of a specimen 

 of this form ( = var. spadicea, Hb. but approaching rufa) gave the 

 following result — 



Scales with 4 teeth formed 10 per cent, of the whole. 



jj b „ „ o_i ,, „ 



100 

 a few with 3 teeth only, amounting to less than ^ per cent., were left 

 out of the calculation. This gave 90 per cent, of the scales as having 

 5, 6, or 7 teeth (89 per cent, of these having 5 or 6) and clearly 

 placed the insect, as to its scales, in the ligula group. A second speci- 

 men, similar to the above but still more approaching var. rufa, showed 

 a like result — 



Scales with 4 teeth formed 3 per cent, of the whole. 



jj S )> }) "* }> }> 



!) b „ „ oA ,, „ 



100 

 or, 97 per cent, of the scales had 5, 6, or 7 teeth and 86 per cent. 5 or 6. 

 On the other hand, similar insects which differed only in having the 

 blunt apex and rounded margin of vaccinii — the true var. spadicea (Hb.) 

 and rufa (Tutt) — showed in one specimen — 



Scales with 3 teeth formed 8 per cent, of the whole. 

 5) 4 ,, „ bU ,, „ 



j> 5 „ „ oi „ „ 



,» t) ,, ,, J- 5, }> 



100 



and in another specimen, 



Scales with 3 teeth formed 8 per cent, of the whole. 

 )j 4 „ „ bo „ „ 



100 



or, 69-5 per cent, of the scales had 3 or 4 teeth only — allying the 

 specimens in this respect to the type of vaccinii. These data tallied with 

 a previous examination of similar specimens some months ago. 



The difficulty frequently experienced in separating C. russata and 

 C. immanata led me to examine a few of both these species, to ascei'tain 

 if any similar differentiation seemed possible. Some six specimens of 

 C. russata and vars. perfnscata, comma-notata and centum-notnta showed 

 a large predominance of scales with 4 teeth, which formed 60 to 80 

 per cent, of the whole, a few only having 3 and 5 teeth. This pro- 

 portion seemed approximately constant. One specimen of C. immanata 

 var. marmorata on the other hand, showed an average of 97 per cent, 

 of scales with 4, 5, or 6 teeth (43 per cent, had 4 only), the remainder 

 having 3 ; but one of the type of C. immanata, with the nearly black 

 median area, showed a preclominance of the scales with 4 teeth to the 



