47 



at some larval instar, though without any definite history it is im- 

 possible to assert that any particular specimen has not a congenital 

 origin. 



Even my specimen of Latiorina orbitidics may be so. I take it up 

 at the last larval instar, when obviously something was wrong with 

 the wing centres of the left side. In the imago the left wings are 

 small, but not otherwise seriously abnormal. It is difficult to believe, 

 had this been of congenital origin, that such definite appearances 

 would have been seen in the larva, or that the pupal wing cover 

 would have been of weak texture, as well as small. 



This example oi L.orbitulus is a very ordinary one as regards the 

 imago, viz. the left wings are both markedly smaller than the right ; 

 the other defects of the specimen are due to leaving it to die and 

 dry up in a small box before pinning and setting it. Its interest 

 consists in my having a drawing of the larva in the last instar, which 

 shows that the ordinary markings are wanting over the site of these 

 wings, and that the wings themselves are in evidence as minute, 

 spiracle-like scars, not proving, but rendering it highly probable, that 

 some injury in an earlier instar had destroyed some dermis with 

 portions of the wing discs. The pupa shows the left wings smaller 

 than the right ones and of weaker texture (PI. I, figs. 1-3). 



All these cases may be interpreted by a reference to my experi- 

 ments and Herr jNIeisenheimer's on L. dispar, which show that accord- 

 ing to the damage done to the wing centres, so one may have 

 complete regeneration, or total absence of the wing, with any inter- 

 mediate condition. 



Three of the L. dispar so experimented on are exhibited ; they 

 show the effect on a hind-wing of interfering with the germinal discs 

 in the larva by means of a needle. Herr Meisenheimer's experiments 

 were more numerous and effective, as he completely and partially 

 destroyed the centre with an electric cautery. 



I exhibit specimens of various species that show absence of a wing, 

 reduction in size, with little other effect, reduction in size with 

 alteration and simplification of markings, washed out, ragged, and 

 otherwise altered and twisted wings. My specimen of lUinessa 

 iiriicce, with one minute hind-wing, suggests that it does not belong to 

 this group, but is a case of one wing failing to expand at all, a rarer 

 occurrence than the other deformities we have here, but a closer 

 examination shows that it is really a fully expanded minute wing. 



The presumption in all these specimens is that regeneration, incom- 

 plete from the late date or extensive character of the injury, is the 

 vefa causa. 



A further malformation of wings is that of extra wings. These take 

 many forms, in fact no two specimens seem to be exactly the same — 

 a strong circumstance in favour of their resulting from regeneration 

 after injury. They are very rare, certainly not i per cent, of the 

 other wing malformations we have just been considering ; and, 

 therefore, their frequency is of a similar order of magnitude amongst 



