[Illustration: Fig. 89.--Cimex Lectularius (Mag.)] _Family 7, Cimicidæ._--The type of this family is the common Bed Bug (_Acanthia lectularia_), which is only too well known to most people. Although treated as a British insect, it does not always appear to have been an inhabitant of these islands, but to have made its way here about the beginning of the sixteenth century. Three other British species have been described as inhabiting the dwelling-places of certain animals and sucking their blood. _A. columbaria_ attacks pigeons. _A. hirundinis_ is found in swallows' nests, and _A. pipistrelli_ feeds on bats. _Family 8, Reduviidæ._--All the insects of this family are predaceous in their habits, and are exceedingly numerous in tropical climates. The largest British species is _Reduvius personatus_, an insect about three-quarters of an inch long, of a blackish-brown colour with reddish legs. It is well furnished with wings, and flies especially in warm summer evenings, when it frequently enters houses, being attracted by the lights. This insect is said to be a great enemy to the bed bug. Some of the foreign species of _Reduviidæ_ are most formidable insects, such as the great black _Conorrhinus renggeri_ of Chili, which often attacks travellers when camping out. _Family 9, Emesidæ._--Most of these insects are carnivorous in their habits. The best known species of this family is probably _Plæaria vagabunda_, a brown, delicately-formed insect, which inhabits trees. [Illustration: Fig. 90.--Acanthaspis Sexguttata.] TRIBE II.--HYDROCORES OR WATER BUGS. All the insects belonging to this tribe are either water insects, or found only in the immediate neighbourhood of water. It contains the remaining families of the _Heteroptera_, six in number. _Family 10, Saldidæ._--The majority of species belonging to this family are small, dull-coloured insects, always found in the neighbourhood, though they are not strictly aquatic. _Family 11, Hydrometridæ._--The habits of most of these insects are herbivorous, and they are all found near water. _Hydrometra stagnorum_ is a black or brown insect, more or less tinged with reddish, and about half an inch long. It is found running on the surface of water, or else on the banks or among water plants, but is not so active as some of the other species. [Illustration: Fig. 91.--Halobates Pictus (Mag.)] _Family 12, Gerridæ._--This family includes some very familiar insects, which may be seen running over the surface of every piece of water. These insects, of which several species are abundant in Britain, have boat-shaped bodies. The typical form is _Gerris lacustris_, which may be met with almost anywhere. They are predaceous in their habits, feeding upon other insects. Some nearly allied, but mostly very small species, with legs even longer in proportion than those of our common forms, are met with at sea within the tropics, and often at a great distance from land.