HYMENOPHYLLEJ3. 



HYMENOPTERA. 



170 



(Burnett, Outlines of Botany ; Berkeley, English Flora, vol. v. ; 

 Fries, Systema Mycologicum.) 



HYMENOPHYLLE^E, a family of Ferns including the British 

 genera Hymenophyllum and Trichomanei. The fronds consist of 

 branched veins, each accompanied throughout by a membranous wing 

 or margin ; a cluster of capsules, nearly spherical, ia seated on one 

 of these veins which projects beyond the edge of the leaf, the cluster 

 being inclosed in a kind of cup-like involucre. 



I. Trichomanei has thecae on an elongated filiform receptacle within 



a cup-shaped involucre of the same texture with the frond. 



T. radicans, Babington, the Bristle-Fern (T. ipeciosum, Wildenow), 

 has fronds three or four times pinnatifid, glabrous; segments uniform, 

 linear; involucres solitary, in the axils of the upper segments; seta; at 

 first included, ultimately very prominent. The frond in fact consists 

 of hard wiry branched ribs, each furnished throughout with a rather 

 membranous wing. Rhizome black, downy, very long. Fronds 

 rather triangular, very much divided, from 4 to 8 inches long. Invo- 

 lucres scarcely winged. 



This is a very interesting fern, on account of its beauty, its rarity, 

 its susceptibility to injury from exposure when in cultivation, and its 

 entire absence from all European countries or islands, with the single 

 exception of Ireland. In texture as well as in scent it resembles some 

 of the marine Alga, and it has been observed to assume a life-like 

 appearance on being immersed in water after being kept perfectly 

 dry for years. At the present time this plant is to be found nowhere 

 but in Ireland, though formerly it is said to have grown at Bell Bank, 

 in Yorkshire. It has been lately supposed by some botanists that 

 there are two Irish species of Trichomanei, the Killarney and the 

 Glouin Caragh plants. Mr. Newman however believes the latter to 

 be merely a variety of T. tpeciotvm, and calls it T. I. Andrewsii. It 

 differs from the former in having lanceolate fronds and winged invo- 

 lucres. It is found hi very damp shady places. No other fern will 

 thrive well in a case with the Trichomanei, the treatment required for 

 one being destructive to the other. The Trichomanei will live or even 

 grow lazily in a glass with other ferns, but will never attain a vigorous 

 state of growth. 



II. Hymenophyllum has the thecse on a narrow subclavate receptacle 



within a 2-valved involucre of the same texture with the 

 frond. 



//. Tanbridyeme, the Tunbridge Filmy Fern, has pinnate fronds, 

 pinnae distichous ; segments linear, undivided, or bifid, spinosely ser- 

 rate ; involucre compressed, spinosely serrate ; rachis broadly winged. 

 It is slender and delicate, the rhizome very long and thread-shaped. 

 Pinna;, rachis, and involucres in the same place. Valves of the invo- 

 lucre adpressed throughout the greater part of their length, slightly 

 gibbous at the base. It is found amongst moss and in shady places, 

 on the surface of rocks and stones, in many places in England, Wales, 

 and Ireland. This plant is the Trifhoma.net Tunbridgentt of Linnaeus, 

 Hudson, and many of our earlier authors. 



11. WiUuni, Wilson's Filmy Fern, has pinnate fronds, pinna; 

 recurved ; segment* linear, undivided, or bifid, spinosely serrate ; invo- 

 lucre inflated, entire, rachis slightly bordered. It resembles the pre- 

 ceding species, but the pinnae curve backward and the involucres 

 forward. The valves of the involucre are convex or gibbous through- 

 out, touching only by their edges, which are quite entire. The range 

 of this species seems to be much more extensive than that of Jf. 

 TunbridyenM ; it also appears to be a more northern species, and 

 generally to prefer a greater elevation ; still the two plants are often 

 intermixed, particularly about the waterfalls in the vicinity of Kil- 

 larney, and it is frequently very difficult to distinguish the one from 

 the other. (Newman, Britith Perm.) 



HYMKN'OTTERA, one of the orders into which Insects are 

 divided. Hymenopteroua Insects possess four membranous wings, of 

 which the anterior pair are the larger ; they have all the usual parts 

 of the mouth well-developed, that is to say, they possess labrum, 

 labium, mandibles, maxilla;, and two pairs of palpi ; besides the 

 ordinary compound eyes, they are furnished with three ocelli, or 

 simple eyes, which are usually situated on the vertex of the head. 

 Their tarsi are 5-jointed. The females are provided with an ovi- 

 positor, consisting chiefly of three elongated slender processes, of 

 which two serve as a sheath to the third. This ovipositor, in many 

 species, is so organised that it can not only perform its ordinary 

 function, but serve as a weapon of defence, and is the part which 

 in bees and wasps is called the sting : in these insects it is barbed at 

 the apex. The antenna are generally filiform or setaceous. The 

 mesothorax and metathorax are well-developed ; the prothorax is 

 narrow. 



Insects of the order Ifymenopttra undergo what is termed complete 

 metamorphosis, that is, the larva is unlike the perfect insect, and the 

 pupa does not possess the power of locomotion. The larvje of some 

 of these insect* very much resemble those of the order Lepidoptera 

 (Butterflies and Moths), but differ in the number of their legs, &c. : 

 these feed upon plant*. [SECUBIFEBA.] The larvae however gene- 

 rally s]>eaking are destitute of legs, and do not possess a distinct 

 head ; and these are for the most part fed by the parent insect, or, 

 as in the cue of bees and wasps, by the neuters. In the pupae, all 



the parts of the perfect insect are visible, since they are inclosed only 

 in a delicate semi-transparent membrane. 



In the imago or perfect state most Hymenopterous Insects live 

 upon flowers, or at least often frequent them, some for the purpose of 

 gathering honey, and others find them a convenient resort wherein 

 they may prey upon the less powerful species of their own class. 



The comparatively simple neuration of the wings will serve to 

 distinguish insects of the present order from those of the order 

 Neuroptera, where the wing is divided by minute nervures into an 

 infinite number of little cells resembling network ; whereas, in the 

 species of the order Hymenoptera, the basal portion of the wings is 

 furnished with longitudinal nervures only, and the apical portion is 

 divided into comparatively few cells, and these nervures and cells are 

 so uniform in species nearly related to each other by affinity, that the 

 absence of some, or even a slight difference in their form, has afforded 

 good characters for the definition of groups. It is to Jurine that we 

 are indebted for this discovery and a very successful application of 

 it. We may remark that the modifications of the marginal and 

 cubital cells and their nervures are those which have been chiefly 

 employed by this author in characterising the various groups. The 

 following figures from Mr. Schuckard's work on ' Fossorial Hymen- 

 optera,' represent one of the anterior wings of a Hymenopterous 

 Insect, in which all the nervures and cells are present. 



1, Ktigma ; 2, radial or marginal cell ; 3, first cubital cell ; 4, second cubital 

 cell ; 5, third cubital cell ; 6, fourth cubital cell ; 7, first discoidal cell ; 8, 

 second discoidal cell ; 9, third discoidal cell; 10, first apical cell; 11, second 

 apical cell; 12, costal cell ; 13, exteruo-medial cell; 14, interno.medial cell; 

 15, anal cell. 



n, costal nerrure ; 6, post-costal nervure ; c, externo-medial nervure ; d, 

 anal ; e, posterior margin ; /, apical ; g, radial ; A, h, h, transverse-cubital ; 

 t, i, recurrent ; j, transverso-medial ; *, discoidal ; (, subdiscoidal. 



The order Hymenoptera is divided by Latreille into two great 

 sections, to which he applies the name of Terebrantia and Aculeata. 

 In the species belonging to the first of these sections the female sex 

 possesses a distinct ovipositor, whereas in the second the ovipositor 

 is replaced by a sting. Many of the ants however form an exception, 

 since they do not possess a sting, and defend themselves by ejecting 

 an acid liquid. In the AciUeata the antenna; are always simple, and 

 composed of 13 joints in the males and 12 joints in the females. The 

 palpi are generally filiform; the maxillary, often the larger, have 



6 joints, and the labial are 4-jointed. The abdomen is composed of 



7 joints in the males, and 6 joints in the females. These two great 

 sections, of which the principal characters have just been given, are 

 again subdivided, the Terebrantia into two sub-sections, and the 

 Acideata into four. 



The firrt sub-section of the Terebrantia, to which Latreille applies 

 the name of Securifera, is thus characterised by that author : 

 Abdomen sessile, that is, it is closely joined to the thorax, of which 

 it appears to form a continuation, and does not possess free motion. 

 The females are provided with an ovipositor, which is most com- 

 monly serrated, and not only used to deposit their eggs, but to 

 prepare a place for their reception. The larvae have always six horny 

 legs, and often others which are fleshy. This sub-section contains 

 two families, the Tenthredinidce and Urocerata. 



The second sub-section, or the Pupivora [PUPIVOBA], have the 

 abdomen attached to the thorax by a slender stalk, which is often 

 very long, and admits of free motion. The larvae are always destitute 

 of feet, and for the most part parasitical and carnivorous. This 

 group is divided into six families : Evanialea, Ichneumonidei [lon- 

 NEUMON], Qallicolas [GALLICOL/E], Chalciditea, Oxyuri, and (Jhryaides 

 [CHBYSIDIDjB]. 



We now come to the sub-divisions of the second great section, the 

 Aculeata. These are four in number, the Heleroyyna, Potsoret, 

 Diploptera, and Anthophita. 



In the Heterogyna the species are many of them composed of three 

 kinds of individuals (as in the Hive-Bee), males, females, and neuters. 

 They have the antennae geniculated, and the ligula is small. Some 

 live in society, and these possess the three kinds of individuals, ol 

 which the males and females are provided with wings, and the neuters 

 are apterous. The Ants (Formica, Linn.) belong to this section. 



