The Scottish Naturalist. 259 



trusion on the part of a stranger would be immediately followed 

 by the violent death of the intruder, but which are not to be 

 found anywhere else. 



The relation which these bear to the ants has not yet, in 

 some cases at least, been satisfactorily explained. Some species, 

 however, seem evidently to be encouraged by the ants, who 

 derive from them the benefit of a constant supply of the same 

 sweet honey-like fluid that they obtain by milking the aphides, 

 while others seem to find a suitable home and food in the nest, 

 and to depend on various contrivances for protection against 

 their involuntary (and possibly enraged) hosts. 



These sojourners in the cities of Formica rufa comprise not 

 only insects of various orders, but also spiders and mites. One 

 of the most interesting is a small moth, Myrmecocda ochraceclla 

 Tgstr., whose connection with ant-hills has been long known but 

 whose life-history has not yet I believe been published. About 

 the end of June and in July, if we examine the blades of grass 

 in the vicinity of a nest of the hill-ant in Perthshire or other 

 parts of the north of Scotland, we shall probably see several spe- 

 cimens of a small yellowish-ochreous moth perched upon them. 

 These moths are not very active and rather prefer to crawl 

 about than to fly. Sometimes when disturbed they get on to 

 the nest and enter some of the doors, the ants appearing, 

 strange to say, to be generally rather frightened for them. The 

 eggs are laid in or on the nest, and the caterpillars, which are 

 white with brown heads and with a few scattered hairs, feed 

 upon the decaying vegetable matter of which the nest is com- 

 posed. As, however, a fat soft juicy larva would be a morsel 

 too tempting to escape the jaws of the ants, the caterpillar con- 

 structs long galleries of small twigs, leaves, &c, fastened together 

 with silk, and thereby protects itself from its hosts. The cater- 

 pillar lives during the autumn, winter, and spring, and about 

 the beginning of June assumes the pupa state inside the gallery. 

 The puparium is about the third of an inch in length, slender, 

 and yellowish-brown in colour. The legs have separate 

 covers, those for the first two pairs lying between the wing- 

 covers, and at the extremity of the wing-covers appear the 

 coverings (nearly free) of the extremities of the third pair of 

 legs. On the dorsal aspect of the covering of the segments of 

 the hind body (except the three penultimate) are two rows of 



