Pupa-Digging 
somehow they must hide, and because they hide they 
are hard to find. One may leave a goodly number of 
caterpillars feeding ona plant, and expect to find the 
pupe in due season (say in the surface soil under the 
plant) ; but when one comes to search for them, not a 
single pupa will be found, The larve, it would seem, 
left the vicinity of their food-plants and sought a safe 
retreat elsewhere in which to pupate. Where is this 
safe retreat likely to be? The requirements are— 
Safety from foes that would devour them, floods that 
would drown them; a site not too wet and cold, nor 
too dry and hard, where cattle are not likely to tread 
them under foot—in short, a sheltered, shaded retreat 
where the soil is moderately loose and moist, say along 
the foot of a low wall, or round the bottom of a tree- 
trunk, or under a not too dense hedgerow, 
In hunting for pupz it is well, if possible, to ascer- 
tain by examination of food-plants whether caterpillars 
have been feeding on them, ‘This is not always 
possible—if, for instance, in the early spring last 
ssummer’s leaves are all gone, and the plants are barely 
visible above ground. So pupa-digging is almost 
always something of a lottery, but by observation and 
experience many a good haul can be made. One “fail- 
me-never” is around the feet of Oak-trees—solitary 
trees for preference, or those skirting the edge of a 
wood and along a roadside, if the surrounding soil is 
moderately free, not too hard, tough, and full of grass- 
roots. Setting out during the early months of the 
year—say in February and March—by carefully raising | 
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