73 



HEMIPTERA. 



HENSLOVIACE.E. 



71 



This definition will iuclude the Linnasan genera Fulgoria, Cicada, 

 Notonecta, Nepa, Cimex, Aphis, Chermes, Coccus, and Thripi, and these, 

 with the addition of the genus Pulejc, constitute the order to which 

 Fabricius applies the name of Ryngota. Without the last-mentioned 

 genus they constitute the order Hemiptera, according to Latreillc, 

 Burmeister, and most of the foreign entomologists ; and the orders 

 Hemiptera and Homoptera according to Leach, Stephens, M'Leay, and 

 several other British authors. 



The Hemijitera are divided by Latreille into two sections ; to the first 

 he applies the name of Heteroptera,And to the second that of Homoptera. 

 [HOMOPTERA.] The Heteroptera are characterised by having the rostrum 

 attached to the fore part of the head ; the elytra coriaceous with the 

 extremity membranous, folding one over the other when at rest, and 

 the first segment of the trunk (or the prothorax) the largest, and 

 forming the most conspicuous part of the thorax. The second section, 

 Homoptera (which by many of the English entomologists is regarded 

 as an order), is distinguished by the proboscis being attached to the 

 lower portion of the head, near the chest; the elytra almost always 

 of a uniform coriaceous texture, with their inner margin straight and 

 contiguous : the three segments of the thorax are united in a mass, 

 and the first is frequently shorter than the second. All the insects 

 of this section feed exclusively on vegetable juices. [HOMOPTKRA.] 

 We shall at present confine our remarks to the first section, or to the 

 true Hemipterous insects. 



In the greater number of the Heteropterous Hemiptera the head. is 

 small, situated on the same plain as the thorax, or nearly so ; the 

 fore part is somewhat produced ; the eyes are of moderate size, very 

 convex, and hence project rather suddenly from the sides of the head : 

 between the eyes there are in many species two ocelli, or simple eyes ; 

 the antenna! are of moderate size, composed of long joints, few in 

 number, and situated in front of the eyes : the part usually termed 

 the thorax in descriptions, but which is in fact the prothorax, is of 

 moderate size, often broader than long, and very frequently produced 

 on each side, so as to form an angular projection ; the scutellum is 

 large, generally triangular ; but in some (the Scutellera, for instance), 

 it assumes the form of the body, and is so large that it completely 

 covers that part ; the body itself is often flat or concave above ; 

 convex and more or less distinctly keeled betieath : when the wings 

 are closed the upper part of these insects generally presents a flat or 

 slightly convex surface, and is seldom very convex. The legs are of 

 moderate size, or not unfrequently long. In certain groups (the 

 C'oreida) the posterior thighs of the males of many of the species are 

 remarkably large, and many Lave the tibiae also large, often broad and 

 compressed. 



The proboscis springs from the fore part of the head, and when not 

 in use is suddenly curved downwards and backwards, and lies close 

 to the under surface of the thorax and between the fore pair of legs. 

 It consists of a jointed process (a), which is grooved upon the upper 

 side, and in this groove there are four seta; (6), or bristle-like organs, 

 which are covered above, at their base, by another appendage (c), 

 which is supposed to be analogous to the upper lip or labrum of 

 mandibulate insects; whilst the four setae probably represent the 

 mandibles and maxilkc, and the jointed process the labrum. In the 

 figure, the setae (4) are represented as disengaged from their sheath (a), 

 ami the labrum is lifted up. When in the ordinary position these 

 organs form together a tube, by means of which the juices of plants 

 or animals arc extracted and conveyed to the oesophagus. 



The Hrtcroptera are divided by Latreille into two families ; the 

 first, or the (ieocorua, are characterised as having the antenna) free 

 longer than the head, and inserted between the eyes and near their 

 anterior margin. The tarsi are 3-jointed, but the first joint is some- 

 times very short. The second family, to which the name of Hydro 

 coritae is applied, have the antenna* inclosed and hidden in a groove 

 beneath the eye ; the tarsi have but two distinct joints, and the eyes 

 ar: generally very large. 



The species of the family Geocoritce are for the most part found on 

 the leaves of trees or small plants ; some there are which do not quit 

 the ground, and there are others which live upon the surface of the 

 writer. The genera Jfydromelra, Gerrii, and Velio, afford examples o 

 this mode of life. [HYDHOMKTRIDA] 



Tim insects belonging to the second family (Hydrocorita) live, as 

 their name implies, in the water, and they prey upon other insects. 



The two funiliM which have just been characterised are by mos 

 entomologist* regarded as sections or subsections rather than families 

 the Utter is in fact an aberrant group, the former containing by fa; 



he greater portion of the species. Regarding them therefore as 

 ections, they may be divided into the following families : 



Geocorisce. 



Family 5. Ctmicidce. 



6. Reduvlidiz. 



7. Uydrometi-ida. 



Family 1. ScuteHeridte. 



2. Ptntatomidx. 



3. Coreida. 



4. Acant/tiidfe. 



ffydrocoriitc. 

 Family 1: AejuWo*. Family 2. Noloncctidce. 



HEMIRAMPHUS. [Esox.] 



HEMITRAGUS. [CAPUE.E.] 



HEMI'TRYPA, a genus of Kossil Polypiaria, in the Limestone of 

 Devonshire, allied to Feneatella. (Phillips.) 



HEMLOCK. [Oomnt] 



HEMLOCK, WATER. [CicuTA.] 



HEMP. [CANNABIS.] 



1 1 I :>IP- AGRIMONY. [Eoi'ATORiuM.] 



II EMP-NETTLE. [GALKOPSIS.] 



HENBANE. [HYOSCYAMUS.] 



HEN HIT. [LAMIUM.] 



HENIOCHUS. [CHATODON.] 



HENNA. [LAWSONIA.] 



HKNSLOVIA'CE^, a very small natural order of Exogens. Of 

 ;hig order there is but one genus. Headovia, and three or four species. 

 They are all natives of the hot and damp parts of the East Indies. 

 They are all trees, with opposite entire exstipulate leaves, and minute 

 racemose apetalous flowers, with as many anthers sessile in the sinus 

 of the calyx as there are lobes of that organ ; a 2-cclled many-seeded 

 ovary, and a single style. 



Jlfiislovla pufirsrens. 

 1, a flower magnilk'il ; 2, a vertical section of the ovary. 



In his 'Vegetable Kingdom' Dr. Liudley says of this order: 

 " After vain attempts at settling the true place of the genus Jfenslovia 

 in the natural system, some specimens with ripe fruit, for which I am 

 indebted to Mr. Griffith, place the question nearly at rest. The habit 

 of the plant was evidently that of Viburnum; but its superior ovary 

 and indefinite ovules forbade any reference to Caprifoils. But Hy- 

 drangeads differ from that order mainly in their indefinite seeds, small 

 quantity of albumen, and constant tendency to produce a superior 

 ovary. Jfentlovia agrees with them still further; the flowers are 

 polygamous, the seeds are winged, which is also the case in Hydrangea 

 cordifolia and others, and the albumen is wholly deficient. The chief 

 distinction consists in the complete adhesion of the styles into one 

 undivided cylinder; but in Hydrangeads we have the same pecu- 



