PIKRINAK: POXTIA PROTODICE. 1169 



Bean obtained eggs August 21, wliicli hatched in four days and gave but- 

 tcrflio8 by the middle of September, so tiiiit tlic different stages are quickly 

 ]);l^iS(■d. The insect hibernates in the chrysalis state. 



Dimorphism. It is now known that the smaller and more lightly 

 marked and much rarer Pieris vernalis of Edwards is only a dimorphic 

 form of the long known Pontia [)rotodice. Like the spring types of the 

 genus Pieris the color of tiie wings is of a less pure white and especially are 

 the nervures of the under surface of the hind wings more heavily marked. 

 Boll, Riley, and Bean have all proved the relationship between these forms 

 by breeding, Mr. Boll in tiie Krst instance, but Mr. Bean has further shown 

 that the butterflies appearing latest in the autumn when the nights become 

 cool, and from then until severe frosts, "progressively appi-oach vernalis,' 

 and he concludes from his breeding experiments that vernalis "is not a 

 variety abruptly contrasting with a type form, but merely the extreme term 

 of a series of variations departing from type. " Boll also states that in Texas 

 P. p. protodice is found from April to September but that th6 cater- 

 pillars found in October all develop in November and December into P. 

 p. vernalis. Doubtless in Texas also the latter form will be found to fly be- 

 fore April and that in the early spring no other type will be found. For 

 this has been the invariable (though limited) experience everywhere, and 

 the premature development of some of the spring type in the autumn as 

 shown by Boll's and Bean's breeding experiments, is what occurs, though 

 certainly in far less considerable proportions, in other dimorphic species. 



Miscellaneous. The flight of the butterfly is rapid, especially when 

 alarmed. 



Dr. Hoy once found a female of this species paired with P. rapae. She 

 laid egn-s on the mustard plant in which the pair was found, and the eggs 

 hatched ; but the larvae were never carried to maturity and unfortunately 

 no notes of what the caterpillars were like have ever been published. It 

 was a rare chance lost. 



Parasites. None whatever were definitely known until within a recent 

 time ; Init I have a chrysalis from which a tachinid fly has emerged ; and 

 I had heard of its being attacked by ichneumons before the appearance of 

 the foUowino- passage by Mr. F. M. Webster, who records the action of 

 Pteromalus puparum (89: 1, 2) : — 



On the morning of August 9 we observed a larva of Pieris protodice Boisd., in the 

 act of transforming to the chrysalis. Near by, and very evidently watching this 

 transformation, were a male and female of this parasite. Tlie trio were observed 

 several times during the early part of the day, the parasites always on guard, as it 

 were, although the female was several times observed to attempt oviposition, in every 

 case, however, being deterred from doing so by the jerking of the larva, now in a 

 semi-pupal state. During one of these visits the male was driven away, but soon re- 

 turned. About 6 p.m., the la.st observation of the day, the transformation of the 

 larva, while not complete, had so far advanced as to prevent the radical movements 

 which had characterized its struggles during the forenoon, and the female was busily 



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