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THE NUMBEK OF LARVAL STAGES OF LYCMNA 



AC IS. 



By F. W. Frohawk, M.B.O.U., F.E.S. 



In Mr. Tutt's new work on ' British Butterflies,' vol. iii., 

 pp. 287-8, dealing with the larval stages of Lyccena acis — 

 Cyaniris semiargus, he quotes my description of the different 

 stages of the larvae which I published in the ' Entomologist,' 

 July, 1908. To these the author has added footnotes, doubting 

 the accuracy of my statements respecting the number of stages 

 which this larva passes through. This, I think, calls for some 

 comment. The two notes in question are as follows : — 



Note 1. — "Frohawk calls this the 'fifth instar,' but seems to 

 have judged this to be so entirely from its difi'erent size and its 

 greener tint, changes that occur apparently in this stage without 

 a moult." 



Note. 3. — ** Frohawk calls this the ' sixth instar ' ; it is most 

 probably the ^fifth. Chapman only notes five instars for those 

 he reared at the same time." 



First, I may point out that I have avoided the use of the 

 word "instar" for that of "stage," and no such word as 

 " instar " occurs in the life-history I published. 



In working out the life-histories of certain species, especially 

 the Lycsenidtie, unless the greatest care is taken in observing 

 most critically the different moults, one is very apt to miss a 

 stage completely, especially when the larvae are very young, and 

 for this reason I always keep a few separate, from the moment 

 of hatching until pupation, for special observation; these few 

 I examine with a lens several times daily, and when necessary 

 at night also, to note exactly what is happening ; in this way I 

 ascertain precisely when they moult, and at once note it down, 

 and after each moult I make a microscopical examination of 

 each individual and compare them with others of the same 

 brood, so as to check any individual variation that might occur. 

 (This way of working out species is hardly what Mr. Tutt calls 

 in his preface " Frohawk's ontogenetic outlines.") Therefore 

 in this manner I not only see the actual moults taking place, 

 but also see the cast skins beside the larvae, which I think no 

 one can doubt is sufficient proof. Regarding L. acis, I not only 

 noted each moult and stage in this way, but also made careful 

 drawings of each stage. 



These particular L. acis larvae, which I worked out from the 

 egg to the imagines, moulted five times, as stated in the 

 published life-history in the ' Entomologist,' July, 1908, p. 165, 

 where I stated — " after fifth and last moult fully grown about 

 two hundred and seventy-five days old " 



I do not wish to infer that Dr. Chapman (whose description 



