X;EROPHYLLUM-YPONOMENTID^E. 



shrubs and trees found in the East and West Indies, 

 as well as in North America. The latter do well in 

 the common garden soil, and are increased by cuttings, 

 or by pieces of the roots. They are known as the 

 toothache tree, and belong to Hutaceae. 



XEROPHYLLUM (Michaux). A genus of 

 North American herbaceous perennials bearing hex- 

 androus flowers, and ranking among the Melanthacece. 

 The genus was called Helonicus by Nuttal. As 

 ornamental plants they deserve notice, and require a 

 peaty soil, where they ripen seeds, by which they 

 may be increased. 



XIPHYDRIA (Latreille; UROCERUS, Jurine ; 

 HYBONOTUS, Klug). A genus of hymenopterous 

 insects, placed by Latreille in the family Tenthrc- 

 dinidcc, and formed by Dr. Leach into a distinct 

 family, Xiphydriidce, but belonging to that of Siricida?, 

 having the body cylindrical, the antenna? inserted 

 close to the mouth, slender at the tips ; the oviposi- 

 tor exserted. These are insects of moderate size, 

 which live in the larva state in the stumps of trees, 

 seeming to prefer those of willow grounds. The type 

 is the X. dromedarius (Sirex of Linnaeus), so named 

 from the elongated neck. The other reputed British 

 species is S. camelus. 



XYELA (Latreille). A genus of minute but very 

 remarkable hymenopterous insects, arranged by La.- 

 treille, but improperly, amongst the sawflies (Ten- 

 thrcdinidd), but having the ovipositor nearly as long 

 as the abdomen, and naked ; the^antenna; are elbowed, 

 the third joint being very long ; the maxillary palpi 

 are also very long, and the wings large. Two species 

 are only yet described, but the writer has seen 

 several others, and possesses both sexes of a very 

 large new species, presented to him by Dr. Klug of 

 Berlin, with the manuscript name of Xyda Dahlii. 

 Very excellent figures of the genus are given by Mr. 

 Curtis in his British Entomology. Latreille states 

 that the larvae reside in the interior of vegetables, or 

 in old wood. Brebisson named the genus Pinicola, 

 in consequence of the species being found in the 

 neighbourhood of fir plantations. There is only one 

 British species, X. pusilla. 



XYLOCOPA (Latreille). A very numerous genus 

 of large exotic hymenopterous insects, belonging to 

 the family of the bees, having the body and legs very 

 hairy, the mandibles in the females spoon-shaped, 

 obtuse, and guttered, with two teeth at the tips ; the 

 upper lip is horny, and ciliated above ; the antenna; 

 are very much elbowed and filiform ; the fore wings 

 have three complete sub-marginal cells, the first of 

 which is divided by a small transparent line ; the 

 third is the largest, receiving two recurrent nerves. 

 These bees resemble large humble-bees, and have been 

 called carpenter bees, from their habit of construct- 

 ing their nests in posts and other wooden erections. 

 The body is generally of a black colour, often par- 

 tially covered with pale-coloured hairs ; the wings 

 often stained with violet, copper, or green, and very 

 shining. The male, in many of the species, differs 

 considerably from the female. In a few species the 

 eyes of the male are large and approximating, and 

 the anterior legs are greatly dilated and ciliated. 

 These insects are chiefly inhabitants of tropical 

 countries, to which they give a peculiar entomolo- 

 gical character. The type of the genus is the 

 Xylocopa violacca, a species which occurs in' the 

 central and southern parts of Europe, of a black 

 colour, with fine violet wings, the female of which 



829 



constructs her cells in dry upright paling?, &c., into 

 which she first bores obliquely for an inch, then 

 changing the direction, she burrows perpendicularly 

 for a foot or more, her burrow being about half an 

 inch in diameter. Having completed this burrow, 

 she commences the construction of her cells, forming 

 them of the gnawed wood which she has collected at 

 a short distance from the nest. Having formed a cell 

 at the bottom of the burrow, and filled it with a sup- 

 ply of pollen paste sufficient for the entire subsistence 

 of one of her progeny (the egg of which she intro- 

 duces into the pollen), she stops up the mouth of the 

 cell with a lid of sawdust kneaded together, which 

 serves as a floor to the superincumbent cell, proceed- 

 ing in this manner until the burrow is filled. As she 

 is several weeks in completing these operations, it is 

 evident that the egg deposited in the lowest cell will 

 produce the perfect insect before the rest ; and in 

 order to prevent it from disturbing the upper indivi- 

 duals, the parent bee has the instinct to construct a 

 lateral opening at the bottom of the cells, which pre- 

 vents the egress of the young bees as they successively 

 arrive at perfection. None of the species of this 

 interesting genus are inhabitants of this country. 



XYLOPHYLLA (Linna3us). A genus of curious 

 evergreen shrubs, chiefly natives of the West Indies. 

 Their flowers are monoecious, and belong to Euphor- 

 biacccE. These plants are remarkable for bearing 

 their flowers on the edges of the leaves. The species 

 are easily increased by cuttings rooted in sand, under 

 a glass, on moist peat. 



YEW TREE. This common and well-known 

 tree has been already noticed under TEXAS ; and it 

 may be only necessary to add here that, though 

 placed in Dioecia by Linna;us, individual trees are 

 found with both male and female flowers upon them. 



YPONOMENTIDyE (Stephens). A family of 

 small lepidopterous insects, belonging to the section 

 Nocturna, distinguished by having generally two, 

 rarely four, palpi ; the wings entire, tho anterior pair 

 mostly long and narrow, with shortish cilia; ; the pos- 

 terior generally large, folded on the inner edge with 

 long cilia 1 ; the body slender, elongated, and often 

 depressed, acute in the females, and tufted at the tip 

 in the males. These insects are of small size, but of 

 considerable diversity in their appearance. From the 

 Torlricida: they differ in having the palpi long and 

 slender, and from the Tincidce in having only two 

 palpi. Some of these insects reside in their larva 

 state on flowers, upon which they subsist ; others are 

 found within the surfaces of leaves, devouring only 

 the parenchyma ; some form extensive webs, and 

 live in society ; others are solitary. Among the sub- 

 cutaneous species are some of the most brilliant of 

 the lepidoptera, their wings being adorned with 

 highly polished scales, and some of them being ex- 

 tremely varied in the number of tints ; others, again, 

 are very plain ; the former set have generally droop- 

 ing palpi, the latter ascending recurved ones. The 

 species, and even genera, are very numerous, includ- 

 ing the japanned, or long-horned moths (Adela, 

 Latreille), which are to be found in the early summer 

 months hovering over bushes in great swarms, and 

 distinguished by the great length of their antennae ; 

 Yyponomenta,compris\iig,Y.evonymcI/a,Y.padclla,&c., 

 the larvae of which reside in webs, and often entirely 

 strip the white thorn hedges of their foliage ; the 

 moths being white, with numerous black spots. 



