us 



The Naturalist. 



as well as the other to pin all such supplanters in his cabinet along 

 with the subjective type he studies. In mammalogy the ichneumon 

 is an animal distinguished as the natural enemy and destroyer of 

 snakes, crocodiles, birds, and various animals. From this creature 

 the ichneumon-fly has derived its name, the two bearing in common 

 a boldness and ferocity by no means insignificant. It would be diffi- 

 cult to specify what insects and other things are not preyed upon by 

 these little demons, but we will content ourselves in naming a few. 

 Of lepidoptera, both macro and micro are punished conspicuously, 

 bombyces and noctuides, pyrales and tortrices, aphides, or plant-lice 

 species of cynips or gall-flies ; others prey upon the eggs of spiders, 

 taking up their residence in the cocoons. Dr. S. van Vollenhoven 

 gives an example of two species of Rogas (circumscriptus and testaceus) 

 discovered by M. Ritsema, of Haarlem, in January, within the nests of 

 birds, " by which fact it is proved that some specimens are enabled to 

 endure the winter frost in the state of imago (or perfect insect) by 

 concealing themselves in birds' nests." This writer also informs us 

 that some species of ichneumon pierce dipterous larva living in mush- 

 rooms. 



Of ichneumonidae there are six sub-families, viz : — ichneumonides, 

 cryptides, agriotypides, ophionides, tryphonides, and pimplides, com- 

 prising no less than 136 genera and 1180 species. It would take 

 volumes to describe the distinctive qualities and peculiarities which 

 make up these species, and even at the finish it is quite possible we 

 might have as many more particulars to enumerate as those already 

 touched upon, without regarding at all the problematic question of 

 variety. We can, however, with safety classify them into two kinds, 

 having regard solely to the method of ovipositing in the female 

 imago, thus : 



1. Ichneumons which require a sharp instrument to penetrate the 

 skins of larvae (PI. iv., fig. 2, 2a); 



2. Ichneumons which require a more mechanical arrangement, 

 more complicate and sensitive, " to feel their way," pierce and deposit 

 their eggs in the domiciles of insects, or into objects of solidity and 

 strength (PI. iv., fig. 3, 3«, 35). 



The first kind conceal their swords in sheaths, so to speak, the sharp 

 cutter reposing in an abdominal groove ; the second kind use instru- 

 ments of a long thready appearance, composed of three distinct parts, 

 each one in itself a lancet, the centre one being preserved when in a 

 state of repose by the two exterior ones. The central cord ends in a 

 point flattened, and jagged or indented towards it, forming, in this 



