EVOLUTION OF INSECT INSTINCT. 105 



tion ill America and England, are found to be very useful in 

 making the farmer independent of the scarcity or the exactions 

 of laborers. Translated for the Popular Science Monthly from 

 the Revue des Deux Mondes. 



* 



EVOLUTION OF INSECT INSTINCT. 



By M. CH. PEETON. 



I WAS a witness in 1887 of a combat between a halictus bee and 

 its sphoecode parasite, a "cuckoo bee," which took place in the 

 open air, outside of the nest. The nests of the Halictus mala- 

 churus (Kirby), which are found excavated in the compact soil of 

 garden walks, are narrower at the entrance than below, and here 

 the sentinel bee closes access with its head. 



The sphoecode, Sphaicodus hispanicus (Wesmael), twice as 

 large as its victims, had to enlarge this entrance to effect its pas- 

 sage. I saw it cut up the sentinel, whose quarters came out with 

 the digging. Very near, a halictus was assisting a dying sister 

 whose j)ollen-loaded feet were still moving. She had without 

 doubt been killed by the sphoecode. Another harvester still sur- 

 vived, and attacked the parasite, biting its legs and wings. The 

 bandit, obliged to stop its task frequently, established itself near 

 the nest and tried to seize the enemy with its sharp mandibles. 

 The halictus at last threw itself upon him, and the two were 

 locked in combat. In an instant the halictus was no more. 



The sphoecode labored for nearly four hours to open a passage, 

 and would perhaps have succeeded if I had not judged it prudent 

 to capture it. It had worked till dark without having advanced 

 more than an eighth of an inch. 



Besides the deductions which other authors have drawn from 

 the observation of insects under similar conditions to these, I 

 found a no less important feature toward the study of instinct in 

 the apparent development at the same time with sociability of a 

 courage which impels the individual to devotion of itself to the 

 common cause. The persistent struggle which my halictus main- 

 tained is, I believe, unexampled in the annals of other Hyme- 

 noptera than ants, wasps, honeybees, and bumblebees. It was 

 not a rush of a moment upon the thief, or a struggle in a narrow 

 corridor where escape was impossible after the fight had begun ; 

 but it was a foot-to- foot battle that lasted nearly a quarter of an 

 hour, in the open field, where the halictus could run away at any 

 moment. The assault was made vigorously, of determined purpose, 

 the contestants fighting in close embrace, and ended in the death 

 of one of them. 



