NOTES ON CALLOPHRYS AVIS. 245 



Notes on Callophrys avis {n-ith plate). 



By Dr. T. A. CHAPMAN. 



Some more specimens of Calluphri/s avis having emerged after 

 having given my account of the species to the Entomological Society 

 of London {Tra)is. Knt. Soc. Loud., 1910, p. 85, and I'roc. Knt. Soc. 

 Land., 1910, p. xxi), I am able to give a few further notes on the 

 range of variation in the species, and to report a very curious result of 

 " forcing." I am also able to present photographs of the living butter- 

 fly taken by Mr. H. Main with that perfection that is in no need of 

 further praise from me. 



To take first the results of " forcing." Expecting tbat the pupa? I 

 had would probably emerge naturally in April, and wishing to leave 

 home during that month, I proposed to get the butterflies out before I 

 left by '• forcing," and accordingly put some pupae in a temperature of 

 60° to 70^ on January 28rd, and the remainder on February 5th. The 

 first unexpected result was that two specimens emerged four days after 

 being so placed, and several others a day or two later. These 

 individuals must have differed from their fellows in having already 

 made some progress in the maturation of the imago at the end of 

 January. After a further few days other specimens emerged, and 

 continued to do so till towards the end of February, when they ceased 

 to appear. There still, however, remained some pupae, and I concluded 

 that my forcing operations had resulted in killing these. However, I 

 left them at ordinary temperature when I left home on April 2nd, and 

 found them unchanged when I returned home on May 13th. The 

 result was very gratifying, as instead of these pupae being dead, it 

 appeared that they might have been most carefully consulting my 

 convenience, as on May 15th a 3' emerged, and others during the 

 following ten days, only two pupae remaining over really dead. The 

 precise explanation of this efi'ect of forcing is not very evident. I 

 ought to say that from the laying of the eggs to placing the pupa? in 

 a warm temperature at the end of January, all were treated alike and 

 had kept fairly well together. The theory I frame on the matter is, 

 that C. flf?.s naturally spreads its emergence over a long period, probably 

 from mid-February to well into Ma}^, perhaps a period of nearer three 

 than two months. Forcing brought out at once those that proposed 

 to be earliest, and hastened forward those that represented emergences 

 up to perhaps mid-April or later. Those booked for later emergence 

 had made no progress towards leaving pupal conditions, and were in 

 consequence rather retarded than hastened by the too early high 

 temperature. 



There is, I think, no record of Callophn/s rubi passing two years in 

 the pupal state, and C. aris (a much more southern insect) would be 

 even less likely to do so. Nevertheless, the eftect on these later pupaj 

 would be quite parallel with that on pup.i? of species that do pass, 

 upon occasion, more than one winter as pupfe. In these species it is, 

 I think, usual rather than occasional, to find that, if pupfe are forced 

 before they have had proof of winter having come (and gone?), an 

 unusual proportion, or even all, refuse to emerge that year, but "go 

 over." It may be easier to appreciate this curious result if tabulated 

 thus : — 



NovKMBKi; 15th, 1910. 



