HABENARIA HALESIA. 



with surprising agility and diving to the bottom of 

 the water. The situation of their eyes adds greatly 

 to their defence, enabling them to see objects both 

 above and bclo\v them. One of our most popular 

 writers on natural history thus describes their pro- 

 ceedings : " Water, quiet still water, affords a place 

 of action to a very amusing little fellow (Gyrimts nata- 

 tor), which, about the month of April, if the weather 

 be tolerably mild, we see gamboling upon the surface 

 of the sheltered pool ; and every school-boy who has 

 angled for minnows in the brook, is well acquainted 

 with this merry swimmer in his shining black jacket. 

 Retiring in the autumn, and reposing all the winter 

 in the mud at the bottom of the pond, it awakens in 

 the spring, rises to the surface, and commences its 

 summer sports. They associate in small parties of 

 ten or a dozen, near the bank, where some little pro- 

 jection forms a bay, or renders the water perfectly 

 tranquil ; and here they will circle round each other 

 without contention, each in his sphere, and with no 

 apparent object, from morning until night, with great 

 sprightliness and animation ; and so lightly do they 

 move on the fluid, as to form only some faint and 

 transient circles on its surface. Very fond of society, 

 we seldom see them alone, or, if parted by accident, 

 they soon rejoin their busy companions. One pool 

 commonly affords space for the amusement of several 

 parties, yet they do not unite or contend, but perform 

 their cheerful circlings in separate family associations. 

 If we interfere with their merriment they seem greatly 

 alarmed, disperse or dive to the bottom, where their 

 fears shortly subside, as we soon again see our little 

 merry friends gamboling as before." Journal of a 

 Naturalist, vol. i. p. 307. When they dive to the 

 bottom of the water in the manner above described, 

 they carry with them a little bubble of air affixed to 

 the extremity of the body. Also they are sometimes 

 to be found flying, their well-formed wings permitting 

 such an operation, whilst the high polish of the body 

 protects them from the action of the water. 



With the exception of a few exotic species, the 

 insects of this family are of a small size, seldom ex- 

 ceeding a quarter of an inch in length, and the 

 largest ones do not reach one inch. Some of the 

 species are found on the margins of the ocean. 

 They emit, when touched, a disagreeable scent, 

 arising from a milky fluid which exudes from the 

 different parts of the body, and which is not readily 

 dispelled. 



The structure of the fore loirs indicates their mode 

 of life, serving as arms to convey the food which they 

 tind floating upon the surface of the water, and which 

 consists of sm;tll dead insects, &c., to the mouth. 



The number of species of this family does not 

 exceed fifty or sixty, and of these not more than eight 

 or nine are found in this country ; of these the 

 Gi/rinm natator is the most common species. It is 

 of a brilliant bronzy-black colour, with the sides of 

 the body and antennas metallic ; the margins of the 

 elytra and legs are reddish. The elytra are orna- 

 mented with lines of impressed spots. It is about a 

 quarter of an inch in length. 



HABENARIA (R. Brown). A genus of tuberous 

 rooted herbs, indigenous to the northern parts of the 

 world, some of which were formerly called orchis ; 

 they all belong to the natural order Orc/iidcee. They 

 are cultivated in shady borders or in frames. 



HABRANTHUS (Herbert). A genus of hardy 



697 



and greenhouse bulbs, some of them remarkable for 

 the fine scent of the flower. They belong to Amuryl- 

 lidea;. They are treated like other bulbs. 



H^EMANTHUS (Linnseus). A highly orna- 

 mental genus of African bulbs, called blood-flower, 

 from the deep colour of their blossoms. They belong 

 to the sixth class of Linnseus, and to the natural order 

 AmaryllidccE. Generic character : spatha of four or 

 six valves, involving many flowers, and persisting ; 

 flowers in a dense bunch ; corolla tubular at the base; 

 limb six-cleft, regular and erect ; stamens imposed on 

 the tube of the corolla protruding ; filaments awl- 

 shaped ; anthers incumbent ; style simple ; berrv 

 three-celled : these bulbs thrive best in sandy loam 

 and moor-earth, requiring no water but when in a 

 growing state, and are increased by offsets. 



H^EMATOPOTA (Meigen). A genus of dip- 

 terous insects, belonging to the family Tabanidte, 

 and distinguished from the gad-flies ( Tabanus proper) 

 by wanting the ocelli, and by the antennae, of which 

 the terminal portion consists but of four joints, some- 

 times cvlindric and subulated, the first being thick, 

 and nearly oval, in the males. These insects, which 

 abound in the neighbourhood of woods, are exceed- 

 ingly tormenting to persons walking in such situa- 

 tions, settling upon the exposed parts of the body 

 with a touch so slight that their presence is not per- 

 ceived until they have contrived to insert their power- 

 ful proboscis into the flesh, causing a very acute pain. 

 They are of smaller size than the Tabam, and their 

 wings are elegantly ornamented with dark spots and 

 rings upon a pale ground. There are several British 

 species, the type of the genus being the Tabanus 

 pluvialis of Linnaeus. The name of the genus is de- 

 rived from two Greek words, signifying sucker of 

 blood. 



H^EMATOXYLON (Linmeus). The H. Cam- 

 pechianum is the logwood of commerce, and belongs 

 to the natural order Legumiiiosce. Logwood is 

 astringent, and both in decoction and extract 

 has a sweetish taste, which makes it preferable to 

 many other vegetable astringents as a medicine. The 

 chief use of logwood is, however, as a dye-stuff; and 

 for this purpose large quantities are imported into 

 this country every year, from the British West Indies, 

 Mexico, and the United States. 



H^MOpORACE^E. The name of a natural 



order containing ten genera, and above twenty-four 



species, chiefly cultivated in greenhouses. The name 



of this order, says Dr. Lindley, is derived from its 



blood colour, indicating its most striking peculiarity : 



the roots of several species of H&modorum, Wuchcn- 



dorfia, and Hentiera, yielding a brilliant crimson dye. 



j The species have equidistant leaves, and six stamens, 



with anthers turned towards the ovarium ; in which 



! last character they differ from the closely allied order 



' of Irideee. They are found, with few exceptions, at 



the Cape of Good Hope and New Holland. 



HAIR GRASS. Is the Aimjiemosa of Linnaeus, 

 one of the British grasses. 



HAKE A (R. Brown). A pretty extensive genus^ 

 of Australian plants, belonging to the fourth class of 

 sexual botany, and to the natural order Proteacea:. 

 The flowers are sweet-scented, and are desirable 

 greenhouse plants, thriving in sandy loam and moor- 

 earth, and propagated by cuttings. 



HALESIA (Linnaeus). A genus of North Ame- 

 rican shrubs or small trees, vulgarly called from the 

 shape, colour, and position of the flowers, snowdrop 



