338 NATURE'S TEACHINGS. 



from side to side, just after the principle of the bradawl, and 

 so proceeds until she has made a hole large enough for her 

 purpose. The blades of the ovipositor are then separated, and 

 the egg placed in the hole, as has been described of the grass- 

 hopper. 



THE upper figure represents one of the large Ichneumon-flies 

 depositing the egg in the grub of some wood- inhabiting larva. 

 How she bores the hole has already been described when treating 

 of Boring Tools, and the process need not again be discussed. 

 The principal point at present is, that after the hole is bored, an 

 egg can pass between the blades of the ovipositor, though they 

 are but little thicker than human hairs. 



One of the most extraordinary instances of this kind of ovi- 

 positor is found in an Ichneumon-fly brought from Bogota. The 

 body, from the head to the end of the tail, is not quite an inch 

 long, while the ovipositor is six inches and a half in length, and 

 scarcely thicker than that of the insect whose portrait is given 

 in the illustration. Nothing is as yet known of its habits, so 

 that the object of this wonderfully long ovipositor is a mystery. 

 But that it should be used like other ovipositors is evident 

 enough, and the chief wonder is, what are the mechanical means 

 whereby an egg can be propelled between blades so long and 

 slender. 



There is a genus of Ichneumon-flies called Pelecinus. They 

 deposit their eggs in wood-boring larvae, and we might imagine 

 that the ovipositor would be a long one. It is, however, ex- 

 tremely short, and the requisite length is obtained by the form 

 of the abdomen, the joints of which are so long and narrow that 

 they almost look as if they had passed through a wire-drawing 

 machine, the length of the head and throat being three-eighths 

 of an inch, and that of the abdomen an inch and a half. This 

 long abdomen belongs only to the female, that of the male 

 being short and club-shaped. 



