JC0V[TATES ZOOLOGICAE XXVI, 1919. 297 



states on the same day in any month of the year. This applies more especiaUy 

 to those of the Aristolochia Division, where there appears to be a constant 

 succession of broods ; while the same may be said of many other famiUes among 

 the diurnal and nocturnal lepidoptera of the district. 



Not having come across a single case of seasonal dimorphism, I find it 

 futile, in such instances at least, to record the dates of capture, though naturally 

 I commenced by keeping all data. 



According to the well-known habit, a habit which is none the less strange 

 and difficult to account for when aU outward conditions appear to be identical, 

 the pupae of Papilios sometimes, but only rarely, in my experience, " stand over," 

 the individual skipping a generation and commingling with the next on emergence. 

 The utility of this custom, as a safeguard to the health and continuity of a species, 

 would appear, however, to be a fine provision of nature. 



Ordinarily with such butterflies as P. anchises, lysander, and polydanias, 

 to instance three groups of Division I, the entire metamorphosis is accomplished 

 in about 55 days, the egg hatching in 7 or 8, the larva being ready to pupate 

 in 4 weeks, while another 19 days generally suffices for the pupal period. As 

 pairing and egg-laying foUow emergence without much loss of time, and the 

 process is repeated, as many as six successive generations are thus shown to be 

 possible in the course of the twelve months. 



A noteworthy feature with the Aristolochia PapUios is that emergence 

 from the pupal condition almost invariably takes place about 8 or 9 o'clock in 

 the morning, seldom before 8 or after 11 a.m. No matter how near to the point 

 of emergence an insect may be during the afternoon or evening, the 

 semi-transparent pupa-shell always clearly predicting its advent, one may go to 

 bed with the assurance that it will not emerge till next morning. 



What the determining factors are, whereby these marvels of intuition are 

 enabled to gauge the position of the sun, is a great puzzle, but it is at least obvious 

 that Ught and heat have very little to do with it. I mention this advisedly, for 

 I afterwards discovered that the Papilios of Division II were not thus controlled 

 by any such minute considerations regarding the particular time of day when 

 they might be expected to put in an appearance. 



Sometimes they would emerge in the morning, but I remember thoas " coming 

 out " after lunch one day, and on another occasion after eight in the evening ; 

 while with hyppason emergence would seem to take place, more often than not, 

 well on in the afternoon or even late at night. It certainly seems most natural, 

 and experience proves that with the majority of butterflies it is the normal habit, 

 to emerge in the morning, while most night-flying moths emerge in the evening 

 or during the night, but even here there appear to be exceptions. 



Particular times, indeed, seem to be selected by different families of moths, 

 Sphingids generally emerging between 6 p.m. and midnight, and Notodonts, as 

 a rule, after midnight. 



Reverting to the newly hatched hyppason, I record a note on its excessive 

 restlessness, which on several occasions resulted in the hopeless battering of its 

 wings before the fly was even dry enough to kUl and set. Once this occurred 

 in the dark between 9 p.m. and midnight with a female which emerged in a 

 Spacious, gauze-covered cage kept in a cool place, but which, after fully expanding 

 her wings, became dissatisfied with her environment. On another occasion, 

 about three in the afternoon, a limp-winged female of this species, which I took 



