368 BBITISH LEPIDOPTEEA. 



chrysalide. . . . pour s'accoupler elle se contente de fendre son 

 enveloppe a la partie anale." It is highly probable that, without 

 exception, the head of the Psychid ? is towards the open end of the 

 case and that copulation is effected by the insertion of the male abdo- 

 men. The marvellous development of the male generative organs 

 (pi. v., fig. 2) of Thyridopteryx ephemerae for mis gives some idea of 

 the specialisation that has taken place in order to meet the necessities 

 of pairing whilst the female remains in the case, her head towards the 

 aperture and the generative organs farthest removed from the point 

 of entry. 



The mode of pairing in the higher Psychids is well illustrated by 

 Chapman's description of the process in Stcmdfussia zermattemis (Ent. 

 Rec, xi., pp. 236-237). He notes that the female moth comes partially 

 out of her pupal shell and sufficiently far out of the silken case to pro- 

 trude her head and then retreats, the object of this movement being 

 evidently to expand the tubular mouth of the silken case which remains 

 open, the aperture being of nearly the same diameter as the opening 

 in the male case by which the pupa emerges. The 3 thrusts the 

 extremity of his abdomen into the open end of the case, proceeding 

 gradually to work into the case the whole of his abdomen, until, in 

 perhaps two minutes, it is buried right up to the thorax, so closely as 

 to push forwards the hindwings by the margin of the case pressing 

 against their bases. The male then becomes quiescent, maintaining 

 this position for about three minutes, when he somewhat rapidly 

 releases himself and flies off. Examining him whilst in situ in the 

 case, the first and second pairs of legs could be seen, but no sign of 

 the third pair, which appeared to be included with the abdomen in the 

 case of the 5 moth, and there appears no doubt that they entered the 

 case with or before the abdomen and were used as a means of drawing 

 the latter into the case. Assuming that it is the rule for the third 

 pair of legs to be introduced in this way into the case, it would afford 

 an explanation of the loss of the tibial spurs that are so well -developed 

 in the earlier (Solenobiid and Fumeid) divisions of the superfamily. 



We have already noticed [ante, vol. i., pp. 23-30) several species 

 of the higher Psychids in which parthenogenesis is said to occur. We 

 still want many definite experiments before we can claim to know any- 

 thing satisfactory about it in the higher groups, although its occurrence 

 is beyond question in the Solenobiids (ante, pp. 157-161, 171-181). Stand- 

 fuss asserts (Schles. Art. Psych., p. 18) that on May 27th he collected 

 . 81 cases of Psyche viadrina, four already spun up, but even 

 these four crawled on being disturbed, hence all larvaa. He then 

 details his very carefully conducted experiments that proved that six out 

 of the 41 ? s of this species produced parthenogenetic larva. Their 

 vitality appeared very slight, and as he had failed to breed partheno- 

 genetic P. stetinensis, in 1877-1878, he did not try to breed them. 

 He further notes that he had never observed parthenogenesis in Sterr- 

 hopterix hirsutella, S. standfussi, or Stenophanes graslinella, and suspects 

 that it never occurs in Acanthopsyche opacella, Pachythelia villosella 

 or Canephora unicolor. 



The eggs are laid in the empty pupa-shell, filling the latter so 

 completely as to leave one with the impression that one still has the 

 pupa under examination. They are usually so delicate that the 

 slightest touch ruptures them and one is at a loss to understand how 



