Pelargoniums, their concentration in Southern Africa, 142. _Pelophila borealis_, Payk., larger in Ireland than in the Orkneys, 33. _Phaleria cadaverina_, Fabr., pallid hue of, 64. _Philhydrus melanocephalus_, Oliv., two states of, frequently indicated, 105. _Phlaeophagus_, apterous in Madeira, 82. _Phosphuga atrata_, Linn., taken with the wings developed, 102. _---- subrotundata_, Leach, the Irish form of the _P. atrata_, 33. _Phytophaga_, preponderance of, in the tropics, 28, 29. _Pieris Brassicae_, Linn., varies in Nepaul and Japan, 34. _Pissodes notatus_, Fabr., unaffected by climate, 30. _Platyomus_, its concentration in S. America, 143. _Platyrrhini_, their peculiarity to S. America, 143. _Pogonus luridipennis_, Germ., lurid hue of, 64. _Pontia Brassicae_, Linn., its introduction into Madeira probably recent, 74. Porto Santo, origin of the name of, 49; a generic area of radiation for certain _Helices_, 130. Predacious insects, less numerous in the tropics, 28, 29. _Prostemma guttula_, Fabr., the development of the wings of, 100, 101. _Psylliodes_, a variable species of, in Lundy Island, 60. _---- erythrocephala_, Linn., two distinct states of, frequently indicated, 105. _---- marcida_, Illig., pallid hue of, 64. _---- nigricollis_, Mshm, a pale state of the _P. erythrocephala_, 105. _---- vehemens_, Woll., varies from isolation, 90. _Pterostichus_, its various divisions are natural ones, 175. _Ptini_, their stature affected by isolation, 74; which characters of, are the most constant, 104. _Ptinus albopictus_, Woll., its changes on the islands of the Madeiran Group, 75-77. _Pupa_, often two distinct states of, 106. _Purpurariae_ of the ancients, probably the Madeiran Group, 141. Pyrenean region, the, perhaps a primary area of diffusion, 130. Reasoning, not sufficient of itself for the formation of science, 159. Red-Admiral Butterfly, its introduction into Madeira perhaps recent, 74. _Reduviadae_, on the development of the wings of a representative of the, 101. Representative species, exemplified by the Madeiran _Helices_, 128, 129, 185; where frequently to be recognized, 183. _Rhyzopertha pusilla_, Fabr., unaffected by climate, 31. Rivers, their power of transporting insects along their course, 149. Saline spots, variation of insects in, 57. Salvages, occurrence of a Canarian form on the, 120, 124. _Saprinus_, a modification of _Hister_ proper, 143. _---- nitidulus_, Fabr., two distinct states of, indicated, 106. _Scarabaeus_, the capture of, out at sea, 150. _Scarites abbreviatus_, Koll., large size of, on one of the Madeira Islands, 88; varies both from isolation and altitude, 91. Sciences, the, should assist rather than oppose each other, 155, 156. _Scydmaenus Helferi_, Schaum, smaller in Madeira than in Sicily, 65.