The genus _Mygnimia_ includes a very large number of species, and has a wider geographical distribution than _Pepsis_, being found in the tropical regions of both the Old and New Worlds, some of them rivalling in size and ferocity the larger specimens of the genus _Pepsis_. In the Insects of this genus there is usually a more or less distinct small space of more pallid colour on the middle of each front wing. _Parapompilus_ is a curious genus consisting of Insects of a great variety of peculiar coloration, and having the wings short, so as to be of little use for flight. _P. gravesii_ is an inhabitant of Chili. _Agenia carbonaria_ and _A. hyalipennis_ are small and feeble Insects inhabiting the south of Europe. _A. carbonaria_ extends to the south of England. They construct, as nests for their offspring, small earthenware vessels, differing in form according to the species, those of _A. hyalipennis_ being vase-like in shape, while those of _A. carbonaria_ are contracted near the mouth, something after the fashion of a wide-mouthed bottle. The Insect is able by some means—Fabre thinks by the use of saliva—to varnish the interior of the vessel so that it will not absorb water; the outside of the cells is, however, not so protected, and speedily crumbles away when exposed to the action of water; hence the vessel is placed in a protected situation, such as in a tree-stump, or a hole in a wall, or even in an empty snail-shell under a heap of stones. The cells are stored with spiders that have been paralysed by stinging and that serve as food for the larva of the _Agenia_. The larva of _A. carbonaria_ has been described, and some particulars as to its habits have been given by Verhoeff. {106}It has been stated that this wasp does not paralyse its prey by stinging, but substitutes a process of biting to prevent the spider from hurting the larva that is to feed on it; and Verhoeff's observations seem to show that the legs of the spider are broken by some proceeding of the kind. The _Agenia_ larva is of peculiar shape, the head not being inflexed, while the pleurae of each segment, from the second onwards, are prominent, so as to give the outline of the body a scalloped appearance. This larva is much infested by an Ichneumon that devours, it appears, not only the larva itself, but also the spider that was destined to be food for the larva. Verhoeff seems to have found some evidence that _Pompilus sericeus_ may also be a parasite on the _Agenia_. The construction of earthenware cells, instead of the burrows usual in Pompilidae, by the species of this genus is one of the cases alluded to in our introductory remarks as to allied Fossores exhibiting different habits. Mr. Pride has recently sent us from Brazil similar earthen vessels constructed by some Pompilid.