34 



III B, that Dyar's III of the thorax is the homologue of a sub- 

 spiracular tubercle of the abdomen and so on". 



His terminology is best understood from the fig. 9 and 10, which 

 are drawn after Quail's fig. 1, 2, 3, 4, PI. IX 19046. 



We see that the confusion between the different writers becomes 

 worse. 



Forbes (1910) wrote a study which unfortunately I was 

 not able to read. According to Fracker(1915 p. 14), „he did not 

 cover the subject of the homotypy of the setae. The few figures 

 he labels, include errors for which he was not responsible, as he' 

 had not given the subject consideration" and (p. 35) „most of these 

 associations would be very difficult to explain and they are wholly 

 unnecessary. The mistakes (confusion of primary and subprimary 

 setae) are due, not to errors in observation but to a failure to 

 take the primitive first stage into account." In the table on p. 40 

 Fracker says that the setae are named by Forbes in about the 

 same way as I have done in fig. 11 and 12 of my PI. I in 

 accordance with his indications. It should be observed that the 

 labelling of the Jugatae slightly differs in the numbers 4 — 6 viz: 



Frenatae absent IV V VI 



Jugatae IV V VI absent 



according to Fracker & a? j^ /x 



By his studies of the pattern of the pupa and imago, J. F. van 

 Bemmelen (1889, 1912, 1913, 1914, 1915, 1916) was led to an 

 examination of the pigment spots of the caterpillars. In 1912 

 I.e. p. 115 he gives a synopsis of the spots on Pier is brassicae, 

 larva pupa, and imago and of the pupa of Aporia crataegi. Following 

 Weismann and W. Muller he calls the spots after the rows in 

 which they lie. He distinguishes : the dorsal, dorsolateral, epistigmal, 

 stigmal, hypostigmal, ventrolateral and ventral rows. The first 

 and the last are median, the others are paired. The number of spots 

 in each row is either one, two or three, a group may replace 

 one single spot. By the blending of the spots occurring on con- 

 secutive segments, stripes are brought about. See PI. I, fig. 13. 



