( xxiv ) 



positive evidence as to the effect upon them of floods. As 

 regards many pupa 1 , which bury themselves in earth in low- 

 lying localities it is certain that lengthened submergence 

 cannot be injurious, for they must frequently be many days 

 under water, yet survive. It does not however follow that 

 pupo3 which habitually are high and dry (and most of the 

 common lepidoptera having subterranean pupae evince a 

 preference for such situations) would similarly escape. With 

 the object of learning something definite on this point, I tried 

 some experiments in the winter of 1901-2, supplementing 

 them in the winter of 1904-5. 



" 1 was able to obtain the following species for the pur- 

 pose : — Phalera hucephala, which buries without a cocoon ; 

 Drepana falcataria (with which a few D. curvaltda were 

 mixed) and Selenia bdunaria, which both form close but thin 

 cocoons between united leaves ; Cochlidion limacodes, which 

 forms a dense egg-shaped cocoon; and Araschnia levana, 

 which is naked, and, being attached, as I have observed in 

 the many hundreds I have bred, to deciduous nettle leaves 

 and leaf-stalks, must pass the winter on or near the ground 

 among the leaves and refuse which gather at the bottom of 

 the stumps of dead stems. 



" The pupa? were kept in unglazed earthenware jars which 

 were placed in an ordinary flat sponging bath which stood on 

 a table close to an open window facing north-west. Many 

 were kept thoroughly submerged during the whole of their 

 periods of immersion, being deprived of any opportunity of 

 floating by means of earth in the case of biwphala, of 

 thoroughly soaked moss in the other cases. In 1902 they 

 were thus submerged from the 2nd February onwards, the 

 weather being very cold, so that ice formed several times 

 upon the water in which they were plunged. 



" The treatment was as follows : — 



Hot 

 Submerged. Removed from the water. 



10 6 day by day for 12 successive days. 



27 6 „ „ 21 „ 



20 about 4 „ „ 5 „ ,, 



12 5 ,, „ 15 



20 5 „ ,, 17 



