Searching foi Pupe 
dorsal half of each abdominal segment is ornamented 
with a ring ofsharp spines. Had you left the creature 
to hatch naturally, it would have used these spines in 
effecting its escape from the cocoon, and also in worm- 
ing its way towards the exit hole. It works in a spiral 
fashion, twisting round and round, and is, so to speak, 
just a living screw-nail, Should you have arrived on 
the scene a day too late, you will find the empty pupa- 
case sticking halfway out of the hole. Plate XI, 
Fig. 4, will show you some of these details, and help 
you to understand this strange and interesting . life- 
history of T. crabroniformis. 
After larva-hunting comes pupa-digging. It requires 
some little knowledge of food-plants and seasons—- 
knowledge more easily acquired and more likely to be 
remembered if learned through experience in the field. 
Book-lore is well enough in studying Nature, but actual 
work in the country 1s the thing that counts in the 
making of a naturalist. To go out and start pupa- 
digging anywhere and at any time is to invite failure. 
Nearly all larve have a particular food plant or plants 
on which they may be seen feeding during certain 
seasons of the year; afterwards they disappear. 
Where? Ofttimes it is very difficult to discover. 
They have many enemies searching for them during 
their pupahood—birds, beetles, moles, mice, and ants, 
all take toll of them—hence the necessity for conceal- 
ment. Practically helpless, they cannot run away, 
neither have they any weapons for defence or offence ; 
so they must hide, in a thick cocoon in some cases, but 
12 
