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 worms 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 several times to the egg already treated, others by different mothers. Well, the number of these cocoons varies greatly. Generally, it fluctuates in the neighbourhood of twenty, but I have come across as many as sixty-five; and nothing tells me that this is the extreme limit. What hideous industry for the extermination of a Butterfly’s progeny!
I am fortunate at this moment in having a highly-cultured visitor, versed in the profundities of philosophic thought. I make way [[371]]for him before the apparatus wherein the Microgaster is at work. For an hour and more, standing lens in hand, he, in his turn, looks and sees what I have just seen; he watches the layers who go from one egg to the other, make their choice, draw their slender lancet and prick what the stream of passers-by, one after the other, have already pricked. Thoughtful and a little uneasy, he puts down his lens at last. Never had he been vouchsafed so clear a glimpse as here, in my finger-wide tube, of the masterly brigandage that runs through all life down to that of the very smallest. [[373]]
[1] A species of Weevils found on thistle-heads.—Translator’s Note. [↑]
[2] .078 inch.—Translator’s Note. [↑]
[3] The author employs this word to denote the insects that are helpful, while describing as “ravagers” the insects that are hurtful to the farmer’s crops.—Translator’s Note. [↑]
[4] This order includes the Ichneumon-flies, of whom the Microgaster is one.—Translator’s Note. [↑]
[5] .117 to .156 inch.—Translator’s Note. [↑]