BLACK-OAK ASSOCIATION 229 



pitch-moth (Evetria comstockiana?} (Figs. 196, 197) (137) which feeds 

 on the new shoots, covering itself with a tent made of pitch and its own 

 excreta. About the bases of the needles, or where pitch is exuding, we 

 often find small larvae resembling Cecidomyiidae fly larvae, but we have 

 found no pitch-midges, chrysomelid flea-beetles, spittle insects, or other 

 enemy of the eastern hard pines which grow in thicker stands. More 

 careful study of these trees at frequent intervals throughout the grow- 

 ing season would probably greatly increase the list of both borers and 

 leaf-feeders. 



The hairy and downy woodpeckers nest in the hollow trees. Their 

 deserted holes are later used by the black-capped chickadee and the 

 screech owl. Farther north the pine grossbeak and crossbill nest in the 

 live pines. The golden-crowned kinglet and the black-throated, green, 

 and pine warblers are abundant here during the migration period. They 

 nest in the pines farther north, and, according to Butler (108), not infre- 

 quently at the head of Lake Michigan. Dr. Stephens photographed a 

 kingbird's nest made from cord from a fisherman's net (Fig. 195). 



The pines prepare the way for the oaks } which appear first as seed- 

 lings, usually becoming more dense with time and finally crowding out 

 the pines. 



Moving dunes and "blowouts" (depressions in the sand made by 

 wind) are common at the head of Lake Michigan. The latter vary 

 from a few feet square and a few inches in depth to some scores of feet 

 in depth and diameter. Dunes, hundreds of feet high, move from place 

 to place. On these the bare-sand conditions of the cottonwood and pine 

 associations occur in areas generally dominated by black oak. Here con- 

 tinue the animals of these two belts, with the possible exception of the 

 maritime locust. The typical black-oak forest always possesses these 

 "blowouts," but surrounding them and under the trees we note the 

 typical herbaceous and shrub growth, and it is with this and the oaks 

 that we are next concerned. 



6. THE ANT-LION OR BLACK-OAK ASSOCIATION 



(Stations 57, 60, 61, 62; Tables L, LIZ, LVI, LIX) 



(Fig. 202) (115, 170, 176) 



Among the black oaks are open spots of relatively stable sand. 

 These small areas may possess some of the same species as the pine areas, 

 but other species give them individual character. In the black-oak 

 stage proper, bare sand is limited. The bronze tiger-beetle (Cicindela 

 scutellaris lecontei) (Fig. 204) which is parasitized by the larva of a bee- 

 fly (Spogostylum anale) (Fig. 205) is abundant 



