232 



DRY AND MESOPHYTIC FOREST COMMUNITIES 



sure on the back of the neck. In this state it can be handled as if dead, 

 laid in any position, or tied into a knot. The only movement it persists 

 in making is that of turning its ventral side uppermost. Ant-lions (Fig. 

 203) are very rarely found at the south end of Lake Michigan, except 

 in the oak belt. They make cylindrical conical pits in the sand (177, 

 179). The most characteristic species under the bark of fallen oaks is 

 the flatbug (Fig. 209). 



b) The field stratum. — This stratum is dominated by many flowering 

 plants, such as Monarda, etc. The addition of a host of insects and 

 spiders not present in the earlier conditions is noticeable. Of the grass- 

 hoppers we add six species (Scudderia texensis, Xiphidium strictum, 



Chloealtis conspersa, 

 Schistocerca rubiginosa, 

 Oecanthus Jasciatus, and 

 Conocephalus ensiger) 



(40). 



The andrenid bees 

 (Agapostemon splendens) 

 and various robber-flies 

 are numerous. On the 

 Monarda the honey-bees, 

 bee-flies (Fig. 210), bum- 

 blebees, and spiders {Mis- 

 times sus asperatus [Figs. 

 207, 208], Dictynafoliacea, 

 Agriope trifasciata, and 

 Epeira sp.) are common. 

 The blueberry is com- 

 monly one of the small herbs of the field stratum and upon it we find 

 several characteristic galls. 



c) Shrub stratum. — This stratum is made up of the choke-cherry, 

 young oaks, rose, etc. The shrub which has been given most attention 

 is the choke-cherry. On this the lacebugs (Fig. 2 1 1) are often numerous; 

 the puss caterpillar (Cerura sp.) (163) sometimes occurs. This cater- 

 pillar has a pair of long projections at the posterior end. When disturbed 

 it extends and waves these projections and thus makes of itself one of 

 the most fantastic of our caterpillars. 



Grapevines are not uncommon on the dunes and we often find a 

 curious red petiole gall on them, which is not common elsewhere. The 

 large fleshy larvae of the achemon sphinx (163) are sometimes taken. 



Fig. 210. — A bee-fly (Bombylius major Linn.) 

 (from Williston after Lugger). 



