Moreover, Ichneumon flies do not confine their attention to cocoons, but often attack well-grown spiders. They invariably lay their eggs on one spot—at the very front of the abdomen, near the cephalothorax, where the spider is powerless to dislodge them. The egg hatches out to a grub which is a veritable “old man of the sea” on the spider’s back, and there it remains until it causes the death of its victim by feeding on the contents of the abdomen. Four such Ichneumon flies have been found to attack the garden-spider, and no kind of spider seems exempt. How they contrive to deposit their eggs in the proper place without great danger of themselves falling a prey to their victims is a mystery. To venture into a garden-spider’s web for the purpose would seem a fool-hardy proceeding. The actual deposition of the egg has seldom been witnessed, but in one of the few cases that have come under observation the spider made little resistance and appeared quite demoralised. It was hanging from a thread, down which the Ichneumon fly was seen to crawl. When it reached the spider the latter dropped an inch lower on two or three occasions but then remained passive, and the parasite on nearing it, turned round, backed down the line, and with great care and deliberation attached an egg at the usual spot. But no enemies of spiders are more terrible than some of the solitary wasps, and gruesome indeed is the fate of any creature that falls into their clutches. The social wasps often capture spiders to feed their young but in their case the proceeding is summary and without any finesse. They merely catch a spider, sting it to death, cut it to pieces with their jaws, and feed it into the mouths of their expectant grubs. The treatment is brutal enough, but at all events it is expeditious. Now the solitary “digger” wasps never see their young. They make cells, either by burrowing in the ground or by agglomerating particles of mud or gravel, and in each cell is placed an egg together with sufficient food to last the grub which hatches out for the whole of its larval existence. The mother will not be at hand—as is the social worker-wasp—to supply new food as required, and it is therefore necessary so to arrange matters that the food provided may retain its fresh condition for at least a fortnight. On the other hand the victims must be deprived of all power of motion, otherwise the egg will stand a great chance of being displaced and crushed, and even if it hatches it will be unable to commence its meal upon the struggling spider.