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XXIII. On Heterogynis paradoxa, Bmhr., an instance of 

 variation hy segregation. By Thomas Algernon 

 Chapman, M.D, 



[Read October lat, 1902.] 



Plate XXVIII. 



Some years ago I had an opportunity of studying 

 Heterogynis pcnclla, and reported some of my observations 

 to this Society (Trans. 1898). I had then no knowledge 

 whatever of H. jiaradoxa, nor any particular hope of ever 

 acquiring any. It was therefore with some pleasure that 

 I came across the species this summer in sufficient numbers 

 to enable me to become familiar with it in several aspects, 

 and some of these seem to be of sufficient interest to be 

 worth reporting. 



The two species of Heterogynis are very much alike, so 

 much so, that to question whether they are really distinct 

 is by no means an irrational attitude. In all those points 

 which makes the genus so interesting they seem to be 

 identical, such as the curious specialization of the female 

 pupa-case ; the organic attachment to, and continuity of, 

 the female moth with the pupa-case at the points where 

 the true legs should exist, this attachment being the only 

 trace of appendages the female moth has ; her exact agree- 

 ment in colouring with that she possessed in the larval 

 state, differing in appearance from the larva only in being 

 smooth and glistening, instead of dull and possessed of 

 tubercles and fine hairs. They are the same also in the 

 way in which the female moth emerges from her cocoon, 

 and rests on the opened top of the pupa-case which 

 partially protrudes from the cocoon, in pairing lasting only 

 for some thirty seconds, and the moth retreating thereafter 

 in five or six minutes into her pupa-case, and in this 

 falling back into the cocoon. If the moth has been out of 

 her pupa for some time, she takes a somewhat longer time 

 to make her retreat. In both species the young larvae 

 when hatched eat up the remains of the parent moth, and 

 then are possessed by an intense desire to wander. They 

 then feed for a time, and hibernate by spinning a small 



trans, ent. soc. lond. 1902. — part iv. (dec.) 



