HICKORY ASSOCIATION 2390 
has become loosened, however, we find practically all the small inverte- 
brates recorded on the ground. The small andrenid bees (Augochlora 
pura) build small cells under the bank and fill them with pollen. One 
egg is laid in each cell (July), and the larva feeds upon the pollen. 
Sowbugs (Cylisticus convexus and Porcellio rathkei) and centipedes 
(Lithobius, Lysiopetalum lactarium, and Geophilus rubens) are common. 
Numerous beetles burrow into the wood or feed on fungi under bark. 
Some of the chief borers are (Cerambycidae) Prionus and Orthosoma 
brunneum, and also Passalus cornutus. The large slug (Philomycus 
carolinensis) is common. 
Fic. 229.—The oak twig pruner (Elaphidion villosum Fabr.) (after Washburn) 
(17th Rept. Minn. Agr. Exp. Sta., p. 165, Fig. 36). 
b) Field stratum.—After rains the slugs and snails, especially the 
young, crawl upon the vegetation. Several flies are common (Sapromyza 
philadelphica). A leaf-hopper (Scaphoideus auronitens), a damsel-bug 
(Reduviolus annulatus), the shield grasshopper (Aélanticus pachymerus), 
and a spider (Theridium frondeum) have all been recorded. 
c) Shrub stratum.—Many spiders build their nests and webs in this 
stratum. Epeira domicilorum was found with a nest of leaves drawn 
together adjoining its web. Epeira gigas, the large yellow spider, builds 
near open places, on high shrubs. The web is a large orb, the nest in a 
convenient group of leaves near the upper side. 
