OPHION MACRURUM. Plate XLIII. fig. 5. ORDER: Hymenoptera. SECTION: Pupivora. FAMILY: Ichneumonidæ, _Leach._ GENUS. OPHION, _Fabr._ Ichneumon, _Drury_. OPHION MACRURUM. Fusco-luteum; alis hyalinis, abdomine thorace triplo longiori ensato. (Long. Corp. 1 unc. 3 lin.) SYN. Ichneumon Macrurus, _Linn. Mant. p._ 540. _Drury, Append, vol._ 2. HABITAT: New York. {93}Head small, dark orange-coloured. Eyes large, black, and oblong. Ocelli shining brown. Antennæ nearly the length of the insect, brown orange, and resembling threads. All the other parts of the insect are of the same brown orange, except the wings, which are transparent. Thorax short. Abdomen three times as long as the thorax, very small at the base, like a thread, but increasing in depth (not in thickness) to the extremity, where it appears square and even as if obliquely cut off; arched from the base to the tip. Legs slender, the hinder ones being the longest. Tips of the tibiæ with two long spines, those of the fore legs having only one. This insect very closely resembles the common English species Ichneumon luteus, Linn. It is, however, considerably larger. After describing this insect our author took occasion to enter into the natural history of the family to which it belongs, namely, the Ichneumonidæ, so named from the Linnæan genus Ichneumon, which last he says, "appears to be taken from its nature and way of life." He then proceeds as follows:-- "It is generally known that butterflies are produced from caterpillars, and that these caterpillars put on different forms before they arrive to that of the butterfly; but few persons know, who have not engaged in this study, that the bodies of these caterpillars are receptacles or habitations for lesser insects, that live and grow within them during a certain time; where they are nourished and fed by the juices of their bowels, till they arrive to a mature age; when, by the appointment of nature, they kill their fosterers, being totally unable to live on any other kind of food but what the intestines of these animals supply them with. The uses and advantages accruing to mankind by the institution of such a genus of insects, together with their natural history, are the subject of the following lines.