30000 species of Hymen- Vespidae (Vespa).

he obtained the girl in marriage, and his happy married life caused him ever afterwards to be invoked in marriage songs (Servius on Virgil, Aan. i. 651). According to another story, he was a youth who was killed by the fall of his house on his wedding day; hence he was invoked to propitiate him and avert a similar fate from others (Servius, loc. cit.). He is represented in works of art as an effeminate-looking, winged youth, carrying a bridal torch and wearing a nuptial veil. The marriage song was sung, with musical accompaniment, during the procession of the bride from her parents' house to that of the bridegroom, Hymenaeus being invoked at the end of each portion. See R. Schmidt, De Hymenaeo el Talasio (1886), and ]. A. Hild in Daremberg and Saglis's Dictionnaire des anliquitéx.

HYMENOPTERA (Gr. bpfyv, a membrane, and 7l'T6/X31/, awing), a term used in zoological classification for one of the most important orders of the class H exapoda (q.v.). The order was founded costa with a row of curved hooks which catch on to a fold along the dorsum of the adjacent fore-wing during fiight. A large number of Hymenoptera are, however, entirely Wingless—at least as regards one sex or form of the species. One of the most remarkable features is the close union of the foremost abdominal segment (fig. 3, i.) with the meta thorax, of which it often seems to form apart, the apparent first abdominal segment being, in such case, really the second (fig. 3, ii.). The true first segment, which under oes a more or less complete fusion with the thorax is known as tire “ median segment ” or propodeum. In female Hymenoptera the typical insectan ovipositor with its three pairs of processes is well developed, and in the higher families this organ becomes functional as a sting (fig. 5)used for offence and defence. As regards their life history, all Hymenoptera undergo a “ complete " metamorphosis. The larva is soft-skinned (cruciform), being either a caterpillar (fig. 6, b) or a legless grub (fig. 7, a), and the pupais free (fig. 7, c), ~i.e. with the appendages not fixed to the body, as is the case in the pupa of most moths. Structure.-The head of a hymenopterous insect bears three simple eyes (ocelli) on the front and vertex in addition to the large compound st by Linnaeus (Sys!cma .Vatz¢, ra.e, 1735), and is still recognized by 1 co 1

After C. L. Marlatt, Bur. Ent. Bull. 3, N.S., U.S. Dept. Agric. 6 7 FIG. 1.-A, Front of head of Sawfiy (Pachynematus); a, 4 labrum; b, clypeus; c, vertex; d, d, antennal cavities. C and D, Mandibles. E, First maxilla; a, cardo; b, stipes; c, galea; d, lacinia; e, palp. B, Second maxiliae (Labium); a, mentum; b, ligula (between the two galeae); c, c, palps. Magnified. 3 9 all naturalists in the sense proposed by him, to include r the sawflies, gall-fiies, ichneumon-flies and their allies, ants, wasps and bees. The relationship of the Hynienoptera to the article HEXAPODA, 10 1] but it may be mentioned here that in structure the highest members of the order are remarkably specialized, and that in the perfection of their in! ° stincts they stand at e WB* V —»— — t he head of all insects I and indeed of all invertebrate animals. About

FIG. 4.-Fore-Wings of Hymenoptera. I. Tenthredinidae (Hylotoma)~ 2 1, marginal; 2, appendieu- 3 lar; 3, 4, 5, 6, radial or sub- 4 marginal; 7, 8, 9, median or 5 discoidal; IO, sub-costal; 6 11, 12, cubital or bronchial; 7 and 13, anal or lanceolate 8 cellules; a, b, c, submarginal Cynipidae (Cynips). Chalcididae (Perilampus) Proctotrypidae (Codfus). Mymaridae (Mymar). Braconidae (Bracon). Ichneumonidae (Trogus). Chrysididae (Cleptes). 9. Formicidae (Formica). nervures; d, basal nervures; 10. other orders of insects is discussed in

- After C. Janet, Mem. Flo. 2.-jaws of H i ve-bee (A pis mellzjira). Magnified about 6% times. a, mandible; b, c, palp and lacinia of first maxilla; 11, e, g, h, mentum, palp, fused laciniae (ligulaor“tongue ) and galea of and maxillae. Soc. Zaol. France (1898). Fig. 3.-Median section through midbody of female Red Ant (My/mica rubra) . H, Head; 1, 2, 3, the thoracic scgments; i., ii., the first and second abdominal segments; i., being the propodeum. optera are now known. Characters.-In all Hymenoptera the mandibles (fig. 1, C, D) are well developed, being ada ted, as in the more lowly winged insects, such as the Orthoptera, for biting. The more generalized Hymenoptera have the second maxillae but slightly modified, their inner lobes being fused to form a ligula (fig. I, B, b). In the higher families this as to form an elaborate sucking-organ or “ tongue." These insects are able, therefore, to bite as well as to suck, whereas most insects which have acquired the power of suction have lost that of biting. Both fore- and hind wings are usually present, both pairs being membranous, the hind wings small and not folded when at rest, each provided along the structure becomes elongated (fig. 2, g) so 0, f, recurrent nervures; sl, 11. Apidae (Apatthus). stigma;v cu, costa. eyes. The feelers are generally simple in type, rarely showing serrations or prominent appendages; but one or two basal segments are frequently differentiated to form an elongate “ scape, " the remaining segments-carried at an elbowed angle to the scape making up the “ flagellum ”; the segments of the iiagellum. often bear eomplex sensory organs. The general characters of the 'jaws have been mentioned above, and in detail there is great variation in these organs among the different families. 'The sucking tongue of the Hymenoptera has often been compared with the hypo pharynx of other insects. According to D. Sharp, however, the hypo pharynx is present in all Hymenoptera as a distinct 'structure at the base of the “ tongue, ” which must be regarded as representing the fused laciniae of the second maxillae. In the thorax the pronotum and pro sternum are closely associated with the mesothorax, but the pleura of the pro thorax are usually shifted far forwards, so that the forelegs are inserted just behind the head. A pair of small plates-the tegulae -are very generally present at the bases of the fore-wings. The union of the first abdominal segment with the meta thorax has been