52 BRITISH LEPIDOPTERA. 



Pyraloids (Yponymeuta) , &c. The terminal hooks by which the Ptero- 

 phorid pupa fixes itself to the pad of silk are specialised and somewhat 

 elaborate, and the cremaster, has, in addition, a separate little group of 

 hooks on the ventral surface of the 8th abdominal segment. It is the 

 latter, possibly, that enables it to assume its normally horizontal posi- 

 tion. Chapman notes that a cremaster is very rare in the pups of the 

 true Tineids and their closest allies, and he states that its use, when it 

 exists, is " not to retain the pupa within the cocoon, but to restrain it 

 at precisely that degree of emergence from the cocoon that is most 

 desirable ; this is usually attained when the movable segments have so 

 far emerged from the cocoon that they are no longer capable of acting 

 in the cocoon as locomotor organs." 



We may here notice that Holland figures (Psyche, vi., no. 190) the 

 pupa of Saturnia arnobia from Kangwe, West Africa, as suspended 

 from a twig by a cremastral attachment, and partly enclosed by a few 

 silken threads spun from a twig or leaf to a neighbouring one. 



The anus of the pupa lies just below the base of the cremaster, at 

 the dorsal end of a long anal furrow which represents the furrow or 

 depression between the two anal prolegs of the larva. 



In vol. i., pp. 59-60, we have given a brief account of the sexual 

 organs in the lepidopterous larva, and pointed out the stage of develop- 

 ment reached during that period. The following remarks, therefore, 

 must be looked upon as a continuation of the notes there to be found. 

 It is really astonishing that the external sexual organs, which are 

 remarkably distinct and conspicuous in many pupae, were not tho- 

 roughly examined long ago. They are to be seen in many old draw- 

 ings of pupte, but no one appears to have recognised what they really 

 were. Katzeburg seems, however, to have been quite aware of their 

 nature and importance and figured (Die Forst-lnsecten, ii., 1840, p. 6) 

 the Heterocerous type of the genital organs on which the apertures 

 are confluent. Wilde, also, was fully aware of the nature of these 

 external structures (vide, Systematische Beschreibung des Raupen, &c, 

 1861, p. 4). Eolleston, in 1870, when making observations on the 

 pupa of Acherontia atropos, recognised that they indicated the normal 

 outlet of the generative glands. In his Schmetterlingsbuch, Berge gave, 

 in 1876, a brief description of the male characters, but Jackson and 

 Poulton published (Trans. Linn. Soc. Loud., 2nd series, vol. v., 1889, 

 pp. 143-212) the first important memoirs on the subject. Since then 

 many observations have been recorded — scattered, however, and gener- 

 ally in magazines. Poulton notes that Lyonet figures (pi. xxxix., fig. 3) 

 a pupa of Cossus ligniperda with distinct male organs, whilst Moore 

 represents (Lepidoptera of Ceylon) some large pupje with indications of 

 the generative structures. Burmeister, in his beautiful illustrations 

 of the Lepidoptera of the Argentine R,epublic, also delineates these parts 

 (e.g., pi. xviii., fig. 11, distinctly represents a male pupa of Attacus 

 hesperus, whilst pi. xx., fig. 5 b is an equally distinct female pupa of 

 Ceratocampa imperialis), and, in the description of these figures, the 

 position of the generative aperture is pointed out, but the sexual 

 differences are not observed. Poulton commenced his studies by an 

 examination of the organs in a male pupa of Sphinx ligustri, and after- 

 wards made a careful comparison of the external generative organs in 

 a large number of species, whilst Jackson (Trans. Linn. Soc. Lond., 2nd 

 ser., v., pp. 146-147) gives a long list of pupas which he has had under 



