76 '' Gjitmndroinorpliisin" and Kliidnd Problems 



long before any dissections were carried out and the term gynandro- 

 morphous or gynandrous was applied to them. The first dissection 

 was carried out in 1825 by Rudolphi on a halved gynandromorphous 

 Gastropacha quercifolia. 



Later it was recognised that, besides the halved, other forms of 

 gynandromorphism also occur and in this country Westwood drew 

 special attention to these and figured several in his Thesaurus Entomo- 

 logicus Oxomensis. The term means no more than the occurrence in 

 one sex of characters belonging to the other, and covers more than one 

 very distinct phenomenon. 



It is much better known and probably much commoner in insects 

 than in other animals. But of other Arthropods, Bertkau gives examples 

 in various crustaceans and two in Arachnida, both in spiders. 



His list includes instances in all the better known orders of the 

 Insecta, in Lepidoptera, Hymenoptera, Coleoptera, Diptei-a, and Orthop- 

 tera. There is little doubt that it is much more frequent in some of 

 these orders than in others, but so much less attention is paid to some 

 and the phenomenon itself is so much less conspicuous in some than in 

 others, that no very exact deduction as to the relative frequency can be 

 drawn. Several thousaftds have been recorded in Lepidoptera, but in 

 Hymenoptera, which are also carefully worked. Dalle Torre and Friese 

 could only collect 90 examples, though they left out those produced in 

 the Eugster hive of bees, which alone numbered some hundreds. 



In Lepidoptera it is unquestionably much commoner in some species 

 than in others, as the lists published by Hagen, Wiskott, and Schultz prove. 



The difference in numbers is real and not apparent, because in 

 Amorpha pupuli, which heads the list, gynandromorphism is not so con- 

 spicuous as in m;iny equally common species, of which onl}' one or two 

 gynandromorphous individuals are known. 



Schultz in his first two lists of gynandromorphs in Palaeartic 

 Lepidoptera gives A. populi 54 examples, Saturiiia curpini 48, Dryas 

 paphia 39, Lymantria dispar 32, and Folyummutas {cams 22. 



Five examples are known in birds. 



Four of these were perfectly halved, a bullfinch, Pyrrliuht pyrrlnda 

 europaea, Vieill, described and figured by Heinroth and Poll, a chaffinch, 

 Fringilla coelebs, Linn., described by Weber, a flicker, Coluptes auratus, 

 Linn., and a species of Daciiis, a South American sugar bird. The fifth, 

 a pheasant described and figured by Bond, was perfectly halved, except 

 in the tail, and tliere was some decussation of sex characters, each feather 

 of both sides being male on the outer and female on the inner side. 



