The Travellers 219 



stantly subject to the hazards of the unforeseen, 

 are silent on this point, of which I clearly per- 

 ceive the importance now that I am trying to 

 arrange my materials in order to write these 

 lines. I find the Sandy Ammophila mentioned 

 as hatching on the 5th of June and the Silvery 

 Ammophila on the 20th of that month ; but 

 my records contain not a word that relates to the 

 hatching of the Hairy Ammophila. It is a 

 detail which, by an oversight, has never been 

 cleared up. The dates given for the other two 

 species come under the general law, which lays 

 down that the perfect insect shall appear during 

 the hot season. I fix the same period, by 

 analogy, as that for the Hairy Ammophila's 

 emergence from the cocoon. 



Then whence come the Ammophilse whom 

 we see working at their burrows at the end of 

 March and in April ? We are driven to the 

 conclusion that these Wasps belong not to the 

 present but to the previous year ; that they left 

 their cells at the usual time, in June and July, 

 got through the winter and began to make their 

 nests as soon as the spring came. In a word, 

 they are hibernating insects. And this con- 

 clusion is fully borne out by experiment. 



If we will but search patiently in the per- 

 pendicular banks of earth or sand facing due 

 south, especially those in which generations of 



