125 



when once the log habitat is developed certain animals are able to per- 

 sist. Nor is the log the only factor of this character in the forest; 

 the moist soil, abounding in vegetable debris, has a similar influence ; 

 and besides, when once a dense canopy is developed the retarded evap- 

 oration and the shade, with the accompanying reduction in heat rays, 

 have a marked influence. The presence of logs and vegetable 

 debris upon the forest floor determines to a very important degree 

 the presence of the land mollusks, diplopods, Termes, Galcrita janus, 

 and Meracantha contractu ; it determines, upon the slopes (Station 

 IV, b,), the presence of Ischnoptera, Melanotics, Passalus cornutus, 

 and Scolecocampa liburna,; and it probably determines, too, many of 

 the ants on the upland and on the forest slopes. Among the forest 

 shrubby growth and tree trunks Epeira verrucosa and Acrosoma 

 rugosa (and probably spinea) spread their webs and appear to thrive 

 only in deep shady woods. A large number of butterflies and moths 

 feed upon the foliage of forest trees, being thus distinctly arboreal, as 

 are also Cicada (nymph, subterranean), Diapheromera, Calosoma 

 scrutator (predaceous), Tremcx columba (and its parasite Thalessa 

 lunator), and Cyrtophyllus pcrspicillatus. Gcotrupcs splcndidus is a 

 ground scavenger. The presence of Ammophila abbrcz'iata is due to 

 the presence of numerous caterpillars on the foliage. 



j. Artificial Glade Community in Lowland Forest 



In the dense humid lowland forest of the Bates woods (Station 

 IV, c) a small open area has been formed by cutting; an artificial 

 glade, as contrasted with a natural open forest. This may be consid- 

 ered an experimental glade. Although it is on the river bottom and 

 completely surrounded by a dense forest community, it is clearly not 

 related to that community, but rather to the open upland forest, and 

 for this reason is here interposed between the discussion of the upland 

 and lowland associations. 



The glade was about 25 feet in diameter; only on the north side, 

 where the sun had the best access, had brush (sassafras) made much 

 progress in closing the borders of this open area. It was therefore in 

 direct communication with the dense surrounding lowland forest. 

 Such a small glade permitted direct sunlight on the ground only dur- 

 ing the middle hours of the day, and it was during this time that ani- 

 mal life was most active. On account of the dense shade of the sur- 

 rounding forest there was little undergrowth, but in parts of the glade 

 there was a dense growth which covered the ground. It was com- 

 posed of grasses, large masses or colonies of Eupatorium ccelestinum 

 in flower, Actinomeris altcrnifolia, with wood nettle (Laportca cana- 



