_Family 20, Proctotrypidæ._--The _Proctotrypidæ_ are probably much less numerous than the preceding family, but have been less studied, being generally smaller and more obscure in their habits; in fact, some of them share with several beetles the reputation of being the smallest insects. [Illustration: Fig. 32.--Proctotrypes Rufipes (Mag.)] _Family 21, Braconidæ._--This family is one of very great extent. Many of the foreign species are rather large and handsome insects, often varied with black and yellow. The best known of the _Braconidæ_ is perhaps _Microgaster glomeratus_, a small blackish species with reddish-yellow legs, which destroys the _larvæ_ of the common Cabbage Butterflies, round the dead body of which its little yellow cocoons may often be observed. _Family 22, Ichneumonidæ._--The _Ichneumonidæ_ are rather large and slender insects, and are divided into many sub-families. [Illustration: Fig. 33.--Bracon Bicolor.] They are a very numerous group. It has been calculated that nearly 5,000 species have been described, but the data generally are very untrustworthy. [Illustration: Fig. 34.--Joppa Antennata.] The species of _Trogus_ are rather large insects, measuring an inch or more in length. They are black with reddish legs and abdomen, and the wings are sometimes slightly dusky at the edges. [Illustration: Fig. 35.--Evania Appendigaster (Mag.)] [Illustration: Fig. 36.--Pelecinus Politurator.] In another group, _Pimplinæ_, the ovipositor is generally very long. The best-known species is _Rhyssa persuasoria_, a blackish insect, which measures about an inch in length. This insect is met with in fir plantations, and uses its extraordinary ovipositor to drill holes in trees infested by the _larvæ_ of _Sirex gigas_, on which its own _larva_ is parasitic. The insect frequently drives its ovipositor so firmly into the wood of the tree, that it is unable to withdraw it, and perishes in this position. _Family 23, Evaniidæ._--One of the most familiar insects belonging to this family is the _Evania appendigaster_. It is a small black insect, found in the south of Europe, and is parasitic on cockroaches. An allied British species, _Fœnus jaculator_, is a not uncommon insect found haunting the burrows of _Crabronidæ_, upon which it is probably parasitic. _Family 24, Chrysididæ._--The Ruby-tailed Wasps, or Golden Wasps, as the _Chrysididæ_ are popularly called, are among the most brilliant of the _Hymenoptera_, most of the species being either of an intense green, blue, or fiery red. They are small or moderate-sized insects, which are found on walls or flowers in the full heat of the sun; for, as a rule, the most brilliantly-coloured insects are diurnal in their habits. [Illustration: Fig. 37.--Chrysis Ignita (Mag.)] As far as their habits are known, they deposit their eggs in the nests of other insects, chiefly _Hymenoptera_, on the _larvæ_ of which their own offspring feed.