PODOPHYLLACE.E POLISTES. 



485- 



introduced into our greenhouse collections, where 

 they thrive in a mixture of loam antl moor-earth, 

 and may be increased by cuttings. The Chinese 

 species are pretty hardy, and promise to be accli- 

 mated so as to stand in our shrubberies. 



PODOPHYLLACE^E. A small natural order of 

 plants, consisting of t\vo genera, \\z.,Podop/iyllum and 

 Jeffersonia, of each a single species. They are erect 

 plants, growing in damp shady places, with stamens 

 twice as many as the petals ; the oviary single, the 

 stigma thick and sub-peltate, and the seeds indefinite. 

 The genera are North American plants. Their roots 

 are said to be cathartic, their herbage narcotic and 

 poisonous, and their fruit eatable, but far from plea- 

 sant. Podophyllum peltatum is the wild lemon or 

 may-apple of the colonists, and its root, whether in 

 decoction or powder, is a valuable aperient, being 

 one of the most safe, easy, and certain known. The 

 plants are increased by division. 



PODURID^E (Leach). A family of apterous 

 insects, belonging to the order Thysanura, Leach ; 

 the head is distinct from the thorax, bearing two fili- 

 form antenna? composed of four simple joints, or with 

 the last of these joints articulated, the parts of the 

 mouth small, mandibulated, the legs six in number, 

 and the abdomen terminated beneath by a forked 

 appendage, applied, when at rest, along the underside 

 of the body, and serving for leaping. These insects 

 are of small size, they are very active in their move- 

 ments, and are generally found in damp situations 

 under stones, decayed leaves, &c., or beneath the 

 bark of trees. Other species are found upon the 

 surface of standing water, where they are, neverthe- 

 less, enabled to execute their leaps. They are some- 

 times found upon the snow, and occasionally they 

 assemble together in considerable numbers, looking 

 like a small heap of gunpowder when seen at a 

 little distance ; when alarmed, however, the entire 

 mass skips off, and soon entirely disappears. It is pro- 

 bable that they feed upon decaying vegetable matter. 



These insects are oviparous, and undergo no meta- 

 morphoses, quitting the egg under the shape which 

 they retain through life, they grow rapidly, arid change 

 their skins. De Geer observed some of them in 

 Holland in a living state, at the time of the greatest 

 eold, their eggs being near them, the latter were of a 

 yellow colour, which became dark red when they 

 were nearly ready to hatch. The young ones, when 

 first hatched, carry their tails stretched out behind. 

 The aquatic species were also observed by him to be 

 able to survive their removal from the water but a 

 very short time ; whence it is most probable that the 

 aquatic species are different from those found upon 

 land. About twenty species have been described as 

 belonging to the genus Podura, including the Podura 

 pliunbea, Linnaeus, of a leaden colour, found under 

 stones, but never met with in society ; Podura aqua- 

 lica, Linnaeus, found in quantities upon standing 

 waters ; P. nivalis, found upon snow and in woods. 



The genus Smynthurus com prises those species which 

 are of a globular form, and have the terminal joint of 

 the antenna" annulated. The type is the Smynthurus 

 fuscus, Latreille, found in moist woods. 



Mr. Templeton has published a valuable Mono- 

 graph upon the Irish species of this family in the 

 second number of the Transactions of the Entomo- 

 logical Society. 



PCECILUS (Bonelli), A handsome genus of 

 coleopterous insects, belonging .to the section Pen- 



lantern, family Carabidee, and sub-family Harpalides ; 

 the body is of an oblong and depressed form, the wings 

 sometimes short, the thorax narrow at the base, the 

 labrum short, truncated mandibles ; with small teeth at. 

 the base, third and fourth joints of maxillary palpi of 

 equal length. These are very active insects, which 

 make their appearance in the early sunshiny days of 

 spring and summer, when they may be seen running 

 with great quickness about footpaths. The type is 

 the Cavabus cup-cus, Linnaeus, a very abundant spe- 

 cies, of a fine coppery-green colour; there are several 

 other British species. 



POINCIANA (Linnceus). A genus of beautiful 

 East and West Indian shrubs, or small trees, belong- 

 ing to LeguiuinoscE. It is called by the colonists 

 Barbadoes flower-fence, and is a highly ornamental 

 plant as well in foliage as in flower. They require 

 the strong heat of a stove to flower well, and may be 

 raised from cuttings or from imported seeds. 



POISON OAK is the Rhus toxicodendron of Lin- 

 naeus, a hardy trailing plant, long ago introduced 

 into our gardens. 



POIVREA (Commelin). A genus of herbs and 

 climbers, bearing fine flowers, and belonging to Com- 

 bretacete. The species of this genus was formerly 

 considered Combretums, but it now forms a section of 

 that genus, distinguished by having ten stamens and 

 five angular seeds. Most of them strike root by cut- 

 tings ; but some of them are so difficult to root, that 

 thev can only be propagated by root grafting. 



POLAN1SIA (Raffles). A genus of pretty an- 

 nual plants, mostly natives of India. Their flowers 

 are dodecandrous, and the genus is ranged among the 

 CapparidacecE. 



POLISTES (Latreille). An extensive genus of 

 exotic hymenopterous insects, belonging to the family 

 of the social wasps (Vcspidce), and distinguished from 

 the typical wasps by the more slender form of the 

 body, the basal segment of the abdomen being smaller 

 and narrower than the second, the wings are lon- 

 gitudinally folded, the eyes internally emarginate 

 or kidney-shaped, and the portion of the internal 

 margin of the terminal part of the mandibles is shorter 

 than the basal part, with the clypeus toothed in the 

 middle. 



The habits of these wasps are in many respects 

 similar to those of the genus Vespa, or true wasps. 

 Like them they reside together in vast societies, com- 

 posed of males, females, and neuters, in nests of vari- 

 able size, containing hexagonal cells. Some of the 

 exotic species construct these nests of a very strong 

 material resembling pasteboard, which they also de- 

 fend by a common envelope. Others, comprising the 

 European species, form their nests of a more papy- 

 raceous substance ; and P. gaUlca, which is common in 

 France, builds its nests on the branches of shrubs, 

 which somewhat resemble a small bouquet or rose, 

 and consist of not more than twenty or thirty cells, 

 which are arranged in a single tier. In some of the 

 species, however, the cells are of a surprising number, 

 and arranged in successive layers supported by pil- 

 lars. It is in the spring that the foundation of these 

 nests are commenced by the female t which was im- 

 pregnated in the preceding autumn. The eggs at 

 first deposited are destined only to produce neuters, 

 which assist her in her labours; but towards the summer 

 she deposits eggs which will bring forth males and 

 females. At this period several of the cells are found 

 to be filled with pure honey. 



