[Illustration: =Fig. 49.=--_Ceraphron niger_ (Curtis) ♂. A tiny black parasitic Chalcid that infests the pupae of the leaf-mining fly (_Phytomyza affinis_). =49a.=--Head of Female. (“Agricultural Gazette,” N.S.W.)] Family 7. Micro-hymenoptera. PROCTOTRYPIDAE. In general appearance these tiny creatures, some of the smallest in the insect world, would seem to be almost identical with those of the previous family; but Ashmead says: “If the anomalous group MYMARINAE are removed there will be no difficulty in distinguishing at a glance a Proctotrypid from a Chalcid,” and defines them thus: “In all true Proctotrypidae the pronotum extends back to the tegulae, and the ovipositor issues from the tip of the abdomen, the sheaths in a few abnormal cases being conjoined and forming a more or less cylindrical tube or scabbard for the reception of the two spiculae and the ovipositor proper.” Sharp on the other hand considers that this is one of the most difficult groups of the Hymenoptera to define; to a specialist of course they can be easily separated, but anyone who first takes up the study of these Micro-hymenoptera (and bear in mind that we are talking about insects, so small that when a collector breeds them out in jars he has to liberate them upon a window pane that he may see them against the light), he will I think endorse Dr. Sharp’s decision. Besides the peculiarities of the abdomen previously noted, the antennae, sometimes twice the length of the whole insect, are composed of from 7 to 15 joints, and in the typical groups, though the first joint may be long, it is not elbowed as in the Chalcids, and is seldom branched. The wings are delicate, without any nervures, except in a few small groups where the veins are somewhat like those of small ichneumon wasps. The hind legs are generally longer than the others, and though some have the thighs swollen as in the Chalcids, they are as a rule much more slender, and the abdomen is usually pointed. They can be bred from galls, particularly those of small Gall-flies (_Cecidomyia_), the eggs of all kinds of insects, and the larvae of small beetles, moths, and other wasps.