THE CABBAGE-CATERPILLAR 317 



of one of my spare vessels. A strip of paper smeared 

 with honey accompanies the new arrivals. 



This happens early in July. Soon, the females are 

 there, fussing about, sometimes to the extent of blacken- 

 ing the whole slab of yellow eggs. They inspect the 

 treasure, flutter their wings and brush their hind-legs 

 against each other, a sign of keen satisfaction. They 

 sound the heap, probe the interstices with their antennae 

 and tap the individual eggs with their palpi; then, this 

 one here, that one there, they quickly apply the tip of 

 their abdomen to the egg selected. Each time, we see 

 a slender, horny prickle darting from the ventral 

 surface, close to the end. This is the instrument that 

 deposits the germ under the film of the egg; it is the 

 inoculation-needle. The operation is performed calmly 

 and methodically, even when several mothers are 

 working at one and the same time. Where one has been, 

 a second goes, followed by a third, a fourth and others 

 yet, nor am I able definitely to see the end of the visits 

 paid to the same egg. Each time, the needle enters and 

 inserts a germ. 



It is impossible, in such a crowd, for the eye to follow 

 the successive mothers who hasten to lay in each; but 

 there is one quite practicable method by which we can 

 estimate the number of germs introduced into a single 

 egg, which is, later, to open the ravaged caterpillars and 

 count the grubs which they contain. A less repugnant 

 means is to number the little cocoons heaped up around 

 each dead caterpillar. The total will tell us how many 

 germs were injected, some by the same mother returning 



