An Encyclopedia of Horticulture. 



253 



Pupa — continued. 

 skin in tlioir origin, and are not present after the 

 larval stage. When the larva is fiall-fed, it crawls away 

 to search out a safe resting-place, and then spins round 

 its middle a silken cord, which is fixed at both ends to 

 the support. The tail, also, is fixed to the support by 

 a pad of silk. The larva then sheds its skin, and the 

 Pupa emerges, of the form shown in Fig. 327. This 

 figure shows the wing-cases protecting the future wings, 

 and also the sheath for the left .antenna. All the limbs 

 of the perfect insect are indicated on the outer shell of 

 the Pupa, though bound down immovably, and all useless 



Fig. 326. Large White Cabbage Butterfly. 



to the insect in this stage. Throughoiit this stage of de- 

 velopment no food can be eaten. The Pupa is often called 

 chrysalis (from the Greek work chrijsos, golden), because 

 of the metallic-yellow spots that appear in the Pupa; 

 of certain common Butterflies, e.g., the Tortoiscshell. 



From the Pupa, usually after the winter has passed, 

 the perfect insect emerges, bursting the skin ou the front 

 half of the back along the middle line, and crawling 

 out. At first, the wings are only the size of the wing- 

 sheaths of the Pupa, but, in an hour or so, they grow 



Fig. 327. Larva and Pupa op Large White Cabbage 

 butteri'lv. 



to their full size, and become stiff and firm, and fitted 

 for flight (see Fig. 326). This example has been selected 

 for description as one in which the Pupa differs much in 

 appearance, powers of movement, and many other points, 

 from the larva on the one side, and from the perfect 

 insect on the other. But, in several large groups of 

 insects, the difference is less marked ; e.g., the Pupa of 

 a wasp has the limbs not bound down to the body, 

 though it moves them little, and cannot eat any food. 

 The Pupaj of beetles resemble those of wasps in this 

 respect. Among certain orders of insects, the metamor- 



Fupa — continued. 

 phosis in incomplete, and the Pupa in these orders 

 usually resembles the perfect insect in all points, except 

 that the wings are represented only by rudimentary 

 organs, quite useless for flight, and the larva differs 

 from the Pupa only in its smaller size, and in the entire 

 absence of any trace of wings. In these, the Pupa 

 is as active, and feeds as voraciously, as the larva. As 

 common insects that exemplify this condition of Pupa, 

 may be mentioned Aphides, Crickets, and Grasshoppers. 

 The helpless Pupa;, such as are met with among Coleo- 

 ptem, Diiitera, Hijmenoptera, and Lepidoptera (see In- 

 sects) are usually protected in a cocoon, spun by the 

 larva when it has reached a safe retreat, though a few 

 resemble the Cabbage Butterflies in making no cocoon. 

 Very often the retreat is underground, many of the larva) 

 burrowing, and making the cocoons in the soil, chiefly 

 of grains of earth, cemented by a silken network, or by 

 a fluid emitted from the mouth. 



FUFALIA (Pupali is said to be the name in the 

 East Indies). Including Desniocliwfa. Ord. Amarantacew. 

 A genus comprising only three species of stove, slightly 

 glabrous or tomentose, trichotomously-branched herbs or 

 sub-shrubs, natives of tropical Asia and Africa. Flowers 

 green, perfect ones solitary, the imperfect ones in fascicles, 

 disposed in interrupted, simple or paniculate spikes ; 

 perianth of the perfect flowers five-parted, the segments 

 lanceolate, acuminate, sub-equal ; stamens five, the fila- 

 ments very shortly connate at base. Leaves opposite, 

 petiolate, ovate or orbicular, obtuse or acuminate, entire. 

 P. atropurpurea is probably the only species in cultiva- 

 tion. It is an evergreen sub-shrub, thriving in sandy 

 loam. It may be increased by means of cuttings, in- 

 serted in sand, under a bell glass, in heat. 

 P. atropurpurea (liark purple). /. dark purple, disposed in 

 spikes, 3iii. tcp 7in. long. .September. I. 2Sin. to 3in. long, fully 

 lin. broail, sleniler, kiiig-stalked, ovate, acuminate, obsoletely 

 mucronulatu, slightly diitted. .Stem striated. Branches purplish, 

 ascendent. //. lift, to 2ft. Tropics, 1759. 



PURGATIVE. A cathartic ; any plant which is 

 used in medicine as an evacuant. 



PUKIPICATIOU' FLOWER. A common name of 

 GalaiiHtus nicalit^. 



PURPLE CARROT-SEED MOTH (Depressaria 

 depresselhi). This insect is, along with congeners already 

 mentioned (see Carrot-blossom Motli and Plat-body 

 Moth), at times, hurtful to Carrots and Parsnips 

 grown for seed, inasmuch as the larva; feed, in company, 

 on the flowers, protected under a slight web, spun over 

 the umbels. When full-fed, they burrow into the stalks, 

 and there become pnp;\;. The moths emerge early. The 

 spread of wings is a little over .^in. The front wings are 

 reddish-brown, with a bent, pale yellowish band near the 

 hind margin, and a large, pale spot on the inner margin, 

 beyond the middle. The head is pale yellow. The larva 

 is green, with a tinge of red, but has the head and 

 second segment black. 



Remediea. The most eSicient is hand-picking the 

 infested umbels, and destroying the larva;. The damage 

 done is seldom very serious. 



PURPLE MEDICK. See Medicago sativa. 

 PURPLE WREATH. See Petraea volubilis. 

 PURPURASCENS. Purplish. 



PURSHIA (named after Frederick Pursh, author of 

 '•Flora AmericfB Septentrionalis," 1817). Stns. Kuiizia, 

 Tigarea. Ord. Rosaceee. A monotypic genus, the species 

 being a much-branched, hardy, evergreen shrub, with 

 scaly buds. It thrives in a sandy soil. Propagated by 

 cuttings of young shoots, inserted in sand, under a hand 

 light, in early summer. 



P. tridentata (three-toothed), fl. yellow, terminal, on short 

 peiluncle.s. July. I. obcuneate, tridentate, crowded on the 

 points of the shoots, hairy above, tomentose beneath. A. 2ft. 

 to 3ft. North.west America, 1826. (B. R. 1446; H. F. B. A. 58.) 



