148 THE ENTOMOLOGIST. 



in his description of S. m. walker'i, clearl}' indicates its true 

 nature. The form zatima or radiata of S. luhricipeda seems to 

 occur ahnost exclusively in Heligoland, but to be quite usual 

 there (see ' Naturalist, ISSH, 220). 



A far more puzzling variation is that of CoUas ednsa (recorded 

 in Entom., 1878, by Mr. E. A. Fitcb), in which the black spots on 

 the fore-wings were distinctly trilobed, and at the same time the 

 outer maigins of the wings were wav}'. The specimen was cap- 

 tured at Colchester. 



b. In the shape and development of the Wings. 



The outline of the wing, especially in species of Lepidoptera, 

 is liable to considerable variation, although the varieties are 

 generally rare. The " tails " of butterflies seem much more 

 variable than any other point in the outline of the wings, as, for 

 instance, in Thais cerisyi (varying from the form caucasica, Ld., 

 with no tails, to the three-tailed deyrollei, Oberth.), and in Cliry- 

 sophanus phlceas, which has a var. eleus, F., described by Stau- 

 dinger as "v. caudata, supra nigricans." Sometimes the wings 

 vary in the direction of being broader or narrower, as, for 

 instance, Colias edusa angustior, Entom., xi. (E. A. Fitch), 

 which had the wings narrower and longer in proportion than is 

 usual. The example was bred, and abnormal external conditions 

 may have led to its peculiarity. 



The late Mr. Pryer has recorded some extraordinary seasonal 

 variation in the shape of the wings of a Japanese Terias. The 

 hybernating form, it appears, is large and has pointed wings, 

 while the summer form is small and with rounded wings. It has 

 been suggested, however, that there was some error in the 

 experiments made, — that the larvae or eggs of T. Iceta were some- 

 how introduced into the breeding-cage, and so gave rise to 

 imagines which were supposed to have come from eggs of 

 hethesha, — but in the face of Mr. Fryer's emphatic declaration 

 that this was not the case, it is difficult to raise that objection. 

 At any rate it is very exceptional, and on the North-American 

 continent, where seasonal variation is so familiar, anything like it 

 is unknown. Mr. W. H. Edwards has kindly given me his 

 opinion on the matter, and writes of the American Rhopalocera : — 

 " I can say this, so far as my experience goes, there is no 

 essential difference in sha]3e of polymorphic forms of one species. 

 What difference there is is in the lengthening or shortening of 

 tail {Ajax), the greater falcation of apex {Grapta interrogationis) : 

 I recall no changes in this line except in these two species. But 

 the changes are of colour, as a yellow Colias from an orange one, 

 etc." (m litt. March 5th, J 888). 



The development of the wings does not always take place as 

 fully as is usual, and tlie consequence is that we have cripples, 



