INSTINCT AND FINAL TENDENCY. 21 



central rib. Then, after having made a slight incision 

 into the main nerve of the leaf, in order to impair the 

 flow of the sap, it cuts across the other half of the 

 leaf a corresponding but more horizontal curve which 

 terminates a little higher on the central rib. After 

 repassing the line of the entire cut to trim the 

 edges and to cut through some nerves still connected, 

 it once more stations itself at the starting-point of the 

 whole operation. With the claws of its legs, whose 

 femurs are powerful levers, it next grasps the edge of 

 the leaf, and walking now downward, now to the 

 middle, it rolls up in less than two minutes one- 

 half of the leaf into a sort of funnel, opening down- 

 ward. After a short repast, which very prudently is 

 taken from parts close to the main ribs, our little 

 worker hastens to roll up the other side of the leaf 

 around the funnel just formed, in which operation it 

 uses its legs in a manner just the reverse of the former. 



Now, after 30 minutes' work, the main prepara- 

 tions have been completed for depositing the eggs. The 

 beetle crawls into the funnel's interior, cuts out three 

 or four little pockets and introduces an egg into each. 

 After this has been done, nothing remains but to close 

 the precious chamber as firmly as possible. To ac- 

 complish this, it walks first to the upper end of the 

 funnel and pierces the different layers of the leaf in 

 such a way as to make them adhere to each other. 

 Then it returns to the lower end of the leaf, and grasp- 

 ing its apex, forms a second funnel, with its opening 

 directed upward and fitting exactly into the larger one 

 (Plate I., fig. 1). 



In doing all this our little architect, otherwise of so 



