PSY 



[ 672 ] 



PTE 



yellow before the young escapes. The 

 Apple Chermes lays its eggs in different 

 places of the twigs of an apple-tree ; 

 usually, however, in the furrows of the 

 knots, and sometimes in a very regular 

 manner. The larvse are scarcely escaped 

 from the egg in the open air, when they 

 hasten to the nearest hud, and hegin to 

 gnaw its scales. On the second day 

 after their birth, they cast their first skin, 

 after which they appear nearly of their 

 former shape and colour. The second 

 changing of the skin can sometimes be 

 scarcely seen at all, because the larva 

 not only puts out a thicker string with 

 the tubercle, but also an immense number 

 of very fine entangled threads or small 

 hairs, which it turns upwards over its 

 back, and with them entirely covers its 

 body and head. In sunshine, these 

 strings look transparent, as if they were 

 made of glass, and become of a greenish 

 variable colour. Under this screen the 

 Chermes are secured from every attack 

 of other insects ; for no ants, mites, or 

 bugs can disturb them in their fortifica- 

 tion, or consume them as their prey. 

 After changing the second skin, the 

 young assume a different colour and 

 form ; they now become light green all 

 over, the abdomen much broader than 

 the thorax, and on the side of the latter, 

 rudiments of the wings are distinctly 

 seen. The third time of changing the 

 skin comes on in about eight days, some- 

 times sooner and sometimes later, ac- 

 cording to the weather. After this skin, 

 the wing rudiments very distinctly make 

 their appearance, and become larger and 

 whiter the nearer the insect approaches 

 to the perfect state. The body is also of 

 a light green, and the larvaB have black 

 eyes, and blackish antennae. At last the 

 time arrives when the insect assumes the 

 perfect state ; it then retires to a part of 

 the leaf which it had selected, and after 

 having firmly fixed itself there, the back 

 splits open, and the beautiful-winged 

 Chermes appears from the nymph. The 

 back of the thorax is of a light green, 

 the abdomen is marked with yellow rings, 

 and the membranous wings with strong- 

 ly-marked, snow-white veins. 



P. cratagi infests the camellia. 



P.ficvs and P. rosce are respectively 

 on the fig and rose-trees. All the species 

 are destroyed by syringing with tobacco- 

 water until the insects are dead, and 

 then syringing with water only. See APHIS. 



PTE 'LEA. Shrubby Trefoil. (From 

 ptao, to fly; winged fruit. Nat. ord., 

 Xanthoxyls [Xanthoxylacese] . Linn., 4- 

 Tetrandria \-J\fonogynia.) 



Pinna'ta requires a greenhouse; cuttings of 

 ripe shoots in sand, under a hand-glass ; sandy 

 loam and peat. Trifolia'ta and its variety are 

 hardy ; seed in April, and by layers in autumn ; 

 any common light soil. 



P. pinna'ta (leafleted). 20. White. May. Nor- 

 folk Island. 1829. 



trifolia'ta (three-leaved). 12. Green. June. 



N. Amer. 1704. 



variega'ta ( variegated- Jeaved). 12. Green, 



June. 1846. 



PTELI'DIUM. (So named from its re- 

 semblance to Ptelea. Nat. ord., Spindle- 

 trees [Celastracese]. Linn., k-Tetrandria 

 1-Monogynia.) 



Stove evergreen shrub. Cuttings of young 

 shoots in sand, under a glass, in heat ; sandy peat 

 and fibry loam, with pieces of charcoal. Winter 

 temp., 50 to 60; summer, 60 to 85, 

 P. ona'tum (egg-leaved). 6. Greenish-white. 

 Madagascar. 1818. 



PTE'EIS. Brake. (From pteron, a 

 wing ; the shape of the fronds, or leaves. 

 Nat. ord., Ferns [Polypodiaceffi]. Linn., 

 %4;-Cryptogamia 1-Filices.) 



All brown-spored. See FEBNS. 



HAEDY. 

 P. aquili'na (eagle-like). 3. July. Britain. 



argefntea (silvery). . July. Siberia. 1816, 



a'tro-purpu'rea (purple). . August. N, 



Amer. 1770. 



cauda'ta (tailed). 2. October. N. Amer. l/77 



peda'ta (double-lobed). . July. Virginia. 1820. 



GREENHOUSE. 



P. argu'ta (sharp-notched). I. August. Ma- 

 deira. 1778. 



Cre'tica (Cretan). 1. July. Candia. 1820. 



escule'nta (eatable)- 3. August. N. S. 



Wales. 1815. 



falcttta (sickle-shaped). 1. June. N. Hol- 

 land. 1820. 



i'ntra-margina'lis (within-margined). 1 . Sep. 



tember. Mexico. 1828. 



Kingia'na (King's) . June. Norfolk Island. 1 831 , 



latizo'na (broad-zoned). l. June. Moreton 



Bay. 1831. 



subverticilla'ta (slightly- whorled). 1. Mexico. 



1831. 



tre'mula (trembling). 3. July. N. Holland. 1820. 



umbro'sa (shady). 3. July. N. Holland. 1823. 



STOVE. 

 P. allnso'ms (allosorus-like). 1. 



a'mpla (large). 6. July. 



calome'lanos (neat-dark). f . September. 



Cape of Good Hope. 1830. 



Cervante'sii (Cervantes'). 1 .July. Mexico. 1824. 



Chine'nsis (Chinese). 2. July. China. 1824. 



colli'na (hill). . August. Brazil. 



corda'ta (heart-shaped). 3. June. Mexico. 1820. 



crenula'ta (scolloped). 2. July. 182/. 



di'scolor (two -coloured). 3.August.Brazil.l825. 



edu'lis (eatable). 3. New Zealand. 1837. 



e'legans (elegant). 3. August. E. Ind. 1824. 

 felosma (heavy-smelling). 5.July.Jamaica.l822, 



