XIV THE EMIGRANTS 195 



certain considerations. One asks if those found bur- 

 rowing so early in April are really insects of that 

 year — i.e. whether these spring workers completed 

 their metamorphosis and came out of their cocoons 

 during the preceding three months. The general rule 

 is that the Fossor becomes a perfect insect, leaves its 

 burrow, and occupies itself with its larvae all in one 

 season. It is in June and July that the greater part 

 of the hunting Hymenoptera come from the galleries 

 where they lived as larvae, and in August, September, 

 and October they follow their occupations as burrowers 

 and hunters. 



Does a similar law apply to Ammophila hirsuta ? 

 Does the same season witness the final transforma- 

 tion and the labours of the insect ? It is very 

 doubtful, for the Hymenoptera, occupied with mining 

 at the end of March, would have to complete their 

 metamorphosis and break forth from the cocoon in 

 winter, or at latest in February. The severity of 

 the climate at that date forbids any such conclusion. 

 It is not when the bitter Mistral howls for a fortnight 

 at a time and freezes the ground, nor when snow- 

 storms follow its icy breath, that the delicate trans- 

 formations of the nymph state can take place, and 

 the perfect insect venture to ' quit the shelter of its 

 cocoon. It needs the soft dampness of earth under 

 a summer sun before it can leave its cell. 



If I did but know the exact date at which Ammo- 

 phila hirsuta leaves the cocoon it would greatly 

 help me ; but, to my deep regret, I do not. My 

 notes, gathered day by day, show the confusion 

 inseparable from researches that are generally 

 dealing with points that cannot be foreseen, and are 



