1912.] 269 



takes place on the underside of a detached slab of rock. The President, 

 a species of Osmia, probably indigotea, Mor., and its cell, from which 

 it had emerged three and a half years after it had l)een found beside a little 

 stream at Jericho, in a hollow stem of Zizyphus spma-christi. It is known that 

 Osmia spp. will sometimes wait through a year or more before emergence. 

 Mr. C. O. Waterhouse observed that in cases of delayed emergence in bees, it 

 was in the larval, not in the pupal state that they passed the interval, and that 

 the larva was capable of existing thus for years without food. Mr. H. Baker Sly, 

 a very dark example of Brenthis sclene, having the under-wings clouded with 

 dark brown all over, except for a slightly lighter shaded spot in the middle, and 

 the upper-wings very heavily clouded with dark brown ; also a specimen of 

 Epuiephele janira, one upper-wing having a white blotch at the tip, the under- 

 wing on the same side also having a white streak. 



The following papers were read: — " Life History of Lonchsea chorea," by 

 A. E. Cameron, M.A., B.Sc. ; communicated by H. S. Leigh, F.E.S. "A few 

 Observations on Mimiciy," by W. J. Kaye, F.E.S. 



NOTES ON SEMI-APTEROUS FEMALES IN CERTAIN SPECIES OF 

 LEPIDOPTERA, WITH AN ATTEMPTED EXPLANATION. 



BY G. V. HUDSON, F.E.S. 



■ The existence of semi-apterous females in certain species of moths 

 has long been known to Entomologists and has been fully described in 

 many entomological works, but as far as I have been able to ascertain, 

 no attempt has yet been made to explain why the semi-apterous con- 

 dition has been assumed by the female sex, or in what respects such a 

 condition can benefit the species. Owing to the limited number of 

 foi-eign works on entomology and the restricted nature of the exotic 

 collections at present available for study in the Dominion, I have been 

 obliged to confine my attention to species inhabiting New Zealand and 

 the British Islands. The circumstances in connection with the occur- 

 rence of flightless females in both these regions prove, however, to be 

 strikingly similar, and this fact merits careful consideration when 

 seeking to obtain an explanation of this interesting phenomenon. It 

 is perhaps needless to point out that the loss of the power of flight in 

 one sex, whilst fully retained in the other, is a very remarkable and 

 interesting circumstance, and the present requirements of Natural 

 History demand, not only that a detailed account of the surrounding 

 facts be given, but that a provisional theory at least be set up to 

 account for it. I should perhaps here point out that these semi- 

 apterous females are quite on a different footing to those insects 

 where the power of flight has been lost in both sexes. The general 



