306 Mr. R. Meldola on the Amount of Substance-waste 



emerge on a morning concluding a period, was weighed in the 

 perfect state, and had lost more than seventy per cent, of its 

 weight on July 22nd. This enormous loss is attributable to 

 the increased activity of the imago, to the drying- up of the 

 moist pupa-case, and to the ejection and drying of that red 

 fluid which most Lepidopterous insects emit on their emergence 

 from the pupa. Similarly Newport found that a pupa of 

 Sphinx ligustri which weighed 67'4 grains had diminished to 

 34 grains when weighed 33 days after (the day after the emer- 

 gence of the imago), having lost 52*1 per cent, of its initial 

 weight. Specimen V. had lost on July 26th nearly seventy-four 

 per cent, of its initial weight ; but even this is smaller than the 

 actual loss, because the first weighing was made more than a 

 week after the changing of the larva, during which time the 

 insect had been losing weight. 



The next experiments were made upon living specimens of 

 L. dispar in the perfect state. Three females and one male 

 were weighed in boxes on July 10th, and then weighed again 

 four days after, with the following results : — 



Table showing loss of weight in four specimens of Liparis dispar 

 (perfect insects) during a period of four days. 



This last table shows in a beautiful manner the relation between 

 activity and waste ; for the male was very restless and fluttered 

 about in its box, while the females were tolerably quiet. The 

 loss in the male is to the mean loss in the females in the ratio 

 of 22-03 : 11*60, which is very nearly that of 2:1. The 

 mean loss in the females is to the mean loss in the four female 

 pupas in the same period of time in the ratio of 11 "60 : 4'99. 



Thus do these preliminary experiments prove that there is 

 a loss of substance in the pupal state, that this loss is different 

 in amount in individuals of the same species exposed to the 

 same temperature, and that it is less in amount than that oc- 

 curring in the same species in the perfect state or in a dead 



