INCIDENTAL PHENOMENA RELATING TO METAMORPHOSIS IN LEPIDOPTERA. 37 



tera anacJioreta and. Notolophus gonostigma will produce partial third 

 broods occasionally, as also will Spilosoma fuliginosa (Bazett), Tephrosia 

 bistortata (Riding), Acidalia subsenceata (Prout), &c. Partial double- 

 broods are recorded frequently in Smerinthus populi, S. ocellatus, one 

 or two examples only in a large brood, Stauropus fagi, pretty general 

 (Holland), Choerocampa elpenor, rarely (Matthews), Euthemonia 

 russula, fairly large part of broods (Hutchinson and others), Nemeo- 

 phila plantaginis (Newnham and Cowie), Clostera pigra (reclusa) (Bowles), 

 Plusia chrysitis (Burrows), P. festucae (Cross), Dipterygia scabriuscula 

 (Burrows), Metrocampa margaritaria (Tutt), Acidalia inomata, Ligdia 

 adustata (Burrows), Pericallia syringaria (Robertson), Tephrosia crepus- 

 cularia (biundularia) , very rare (Bacot), and numberless other species. 



This brings us to a very peculiar fact, viz., the tendency that 

 hybridity has to unsettle the regular habits, as it were, of the parent 

 species as to time of emergence, and the production of continuously 

 brooded progeny. This has been repeatedly observed with regard to the 

 hybrids of Smerinthus populi x ocellatus, most of which appear 

 to emerge in the autumn, Tephrosia crepuscularia x bistortata (vide, 

 Trans. Ent. Soc. Lond., 1898, p. 39) Amphidasys strataria x betularia, 

 bred by Chapman, and emerged in late autumn, &c. 



Our present knowledge of the changes that occur within the pupa 

 during the progress of the development of the wings leads us to mention 

 a fact that has not yet been very satisfactorily explained, viz., the pro- 

 duction of a lepidopterous imago and parasite from the same pupa, the 

 former usually, of course, more or less imperfect. One can only surmise 

 that the larva of the parasite fed on the non-vital tissues of the larva (fat- 

 body, &c), and pupated before the development of the vital organs of 

 the imago, resting in its quiescent pupal form during the latter period 

 of the host's development. Kiinckel, however, notes {Ann. Ent. Soc. 

 France, 4 ser., vol. iv.) the appearance of Arctia caia $ , which 

 emerged with crippled wings and was accompanied on its emergence 

 by a living larva of a dipterous (at first recorded as " hymen - 

 opterous ") parasite. Here the larva must have been actively feeding 

 or absorbing during imaginal development. Similarly Robmeau- 

 Desvoidy notices (Essai sur les Myodaires, ii., 1830, p. 28) that he has 

 seen Phyrae emerge from the imago of Sphinx ligustri. Hearder notes 

 (Ent. Mo. Mag., xx., p. 22) that a larva of Centra furcida, when full- 

 fed showed symptoms of internal disease, and that, soon after, the 

 pupa-case of an ichneumon projected through the skin of the larva. 

 The projecting portion of the pupa was crushed^ and the lepidopterous 

 larva afterwards made a well-formed cocoon, from which, in due time, 

 an imago emerged. To follow up the subject would occupy much 

 more space than we can afford, and we only mention it as an interest- 

 ing subject of enquiry from a biological standpoint. 



Talbot observes (Ent., vii., pp. 15-16) that, in some pupse, the 

 imagines emerge by means of the hydraulic pressure obtained through 

 emitting several drops of fluid from the anus into the empty anal 

 space of the pupa, and thus forcing up the imago until it bursts the 

 pupal case. The species observed were Trochilium bembeciforme and 

 Nonagria arundinis. 



Horn notices (Ent. Mo. Mag., L, p. 51) a specimen of C. vinula that 

 he extracted from the pupa-case, whose wings remained for two whole 

 days as little lappets about a quarter of an inch in length, the wings then 



