LÉPIDOPTÉROLOGIE COMPARÉE 353 



have been cylindrical. I take a ring of copper wire of about 

 20 cm. diameter and cover it with book muslin. I then take a 

 sleeve af the same muslin about 45 cm. in length and sew it to 

 the ring so as to make a cylinder with the ring at one end. Next 

 I sew dovvn the side of the sleeve and finally fix another ring like 

 the first inside but 15 cm. from the mouth. I thus have a neat 

 cylindrical cage into which the insects are placed. The open end 

 is then tied with string, and the cage laid on its side until pairing 

 takes place, when it is inverted, so that the insects can lay their 

 ova in the crevices which form naturally where the cage is tied. 



To secure pairings. 



The best results are obtained by using an excess of females, as 

 the maies, instead of disturbing each other seem to settle down at 

 once if they intend to pair. It is generally stated that the présence 

 of an additional cage containing reciprocal pairs assists pairing. 

 I &nd this to be of no help whatever. If pairing is going to take 

 place, it does so in any case, and the factors that assist it are 

 meteorological ones. A gentle through current of warm air is a 

 very great aid, but, even with this help, if the wind is in the north 

 or east out of doors, pairing may by delayed indefinitely. Fortu- 

 nately, ail the species are very longlived and pairings may be 

 delayed for 14 or 15 days, and then be satisfactorily obtained in 

 the end. Gentle forcing of hirtaria pupae may be necessary to 

 cause their émergence to synchronise with that of the other s. 



Variation of ease in obtaining pairings. 



The various maies (or possibly the females) behave very errati- 

 cally in respect to ease in pairing. I hnd that P. pomonaria maie 

 pairs at once with any species presented to it. This, of course, 

 dépends too on the acquiescence of the female. Hirtaria malc, 

 too, seems to pair readily with, and be accepted by, any females. 

 In default of a female they will pair with each other and then 



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