( XXVI ) 



suddenly on the 3rd or 4th stage, without passing through a 

 spot stage. Mr. Poulton's view is that they indicate the 

 decline of an old character, but this Mr. White also thought 

 unsatisfactory, for the reason that if they were vestigial they 

 would certainly recur in the younger phyletic stages, rather 

 than after the later ecdyses. The testimony of Dr. Weissmann 

 is that in his observations he invariably found them appeal- 

 first in the later stages, and then increase in intensity. This 

 would appear to be attested by the series of examples exhibited 

 here. 



The red spots which occur sometimes, but with greater 

 rarity, upon larvae of Papilio podalirius are similar in general 

 character to those of Smerinthxis populi and oceliatus, but they 

 are unlike them in their distribution ; in one of the specimens 

 exhibited they are in pairs upon nearly all the abdominal 

 segments, forming two longitudinal dorsal rows ; but in 

 another example they exist upon the anterior segments only, 

 where in each case they are clustered more numerously in 

 less regular arrangement. In this species they are also more 

 sharply defined and circular, although there is an irregular 

 red blotch upon the dorsal area of the 3rd thoracic and 1st 

 abdominal segments, in addition to the spots. 



After entering into the open question of the connection 

 between the Smerinthus spots and leaf-galls, and the objective 

 use of such relations, Mr. White said he considered that, in 

 spite of the plausibility of the resemblance they bear to the 

 nidus of some species of gall insects which affect the proper 

 leaves to these red spots, and although some other facts seem 

 to favour that theory, there is no evidence whatever forth- 

 coming to show how the process of simulation could be 

 effected. Moreover, when the species of gall are considered 

 in detail, in relation to time, it appears still more improbable 

 that there is any connection existing between the spots and 

 insect-galls. 



In conclusion, Mr. White said he agreed with Prof. Weiss- 

 mann in his view that the red spots upon these caterpillars 

 form a new character in process of development, — within 

 these restricted limits, — but whether such conspicuous spots 

 upon species so admirably protected will prove beneficial or 



