384 INSECTIVOEOUS PLANTS. 



2. A conducting surface, formed of glassy cells, with deflexed processes 

 overlapping like tiles of a house, forming a surface down which the 

 insect slips, and aflfording no foothold to an insect attempting to 

 crawl up again ; 3. Below this a glandular surface (seen in S. pur- 

 purea), which is sinooth and polished, and is formed of sinuous cells, 

 studded with glands ; 4. A detentive surface occupying the lower part 

 of the pitcher. This last, in some cases, extends nearly the whole 

 length of the pitcher. It has no cuticle, and is studded with deflexed 

 rigid hairs, which effectually detain insects. It is probable that these 

 pitchers, which are so variously constructed, may act in different ways. 

 Numerous insects, such as ants, hymenoptera, heteroptera, coleoptera, 

 flies, cockroaches, moths, butterflies, araohnida, and myriapoda, have 

 been observed in a dead state in the fluid at the bottom of the pitcher. 



There are some insects which are not destroyed by the plant, but 

 which make use of it. Xanthoptera semicrocea (Guen.), a small glossy 

 moth, walks with impunity over the inner surface of the pitcher. The 

 female lays eggs near the mouth of the pitcher, and the young larva, 

 by weaving a thin gossamer-like web, closes up the mouth, and feeds 

 on the substance of the tube. Another insect, which feeds on S. 

 variolaris and S. flava, is a fleshy fly, called Sarcophage sarracenise. 

 Insects accumulate in large quantities at the bottom of the pitchers, 

 and seem to be far in excess of what the plant requires for digestion. 

 They become decomposed, and other insects, which are not entrapped, 

 drop their eggs into the open mouths of the pitchers, to take advan- 

 tage of the accumulation of food. Old pitchers are consequently some- 

 times found full of living larvae and maggots, showing that the fluid 

 had become exhausted and could not injure them ; and insectivorous 

 birds slit open the pitchers with their beaks in order to get at the 

 contents. 



In the pitcher of Darlingtonia saccharine matter is formed, and 

 its pitchers become crammed with large moths. Hooker has examined 

 the pitchers of Nepenthes (the true Pitcher Plant), (fig. 200, p. 95), 

 of which there are above 30 known species, inhabiting chiefly the 

 hotter parts of the Asiatic' Archipelago. He finds in these pitchers also 

 an attractive, conductive, and secreting surface. There is also a glan- 

 dular surface secreting a fluid which appears to act on nitrogenous 

 substances. He found that fragments of meat rapidly dissolved when 

 placed in the"fluid. Pieces of fibrine disappeared in two or three days; 

 cartilage was reduced to a clear transparent jelly. He thinks it pro- 

 bable that a substance acting as pepsine is given ofi' from the inner 

 walls of the pitchers, but chiefly after placing animal matter in the 

 fluid. Voelcker found that the fluid in the pitchers of Nepenthes 

 distillatoria, in the Edinburgh Botanic Garden, consisted of water, con- 

 taining in solution malic acid and a little citric acid, chloride of 

 potassium, carbonate of soda, lime, and magnesia. The fluid was col- 



