LOW PRAIRIE 



285 



sawfly (Fig. 287), which is very abundant in early June. Associated 

 with this are many caterpillars (174). The greasy cutworm (A gratis 

 ypsilon Rott.) feeds upon the strawberry. The army worm (Lucania 

 unipuncta Haw.) feeds upon a variety of plants, and several of its near 

 relatives occur. The larvae of the salt-marsh caterpillar (Estigmene 

 acraea) (Figs. 290, 291), the yellow bear (Diacrisia mrginica Fab.) (Fig. 

 292), hedgehog caterpillar (Isia Isabella S. and A.), and Apantesis 

 phalterta Harr. are common. 



Of the Orthoptera, Xiphidium fasclatum and the 2-lined locust (Melano- 

 plus bivittatus) , the red-legged locust (Melanoplus femur-rubrum) , and 

 the short-winged brown locust (Stenobothrus curtipennis) (Fig. 293) 

 are most characteristic. 



FIG. 292. The yellow bear: o, larva; 

 b, adult (Diacrisia mrginica Fabr.) ; nat- 

 ural size (after Forbes). 



FIG. 293. The short- winged brown 

 locust (Stenobothrus curtipennis) (after 

 Lugger). 



On the flowers are many flower-frequenting flies, viz., Sparnopolius 

 flavins Wied., Asilus sp., Syritta pipiens Linn., Coenosia spinosa Walk., 

 Paragus angustifrons Loew., Pachryrhina ferruginea, and Helophilus 

 conostoma Will. Preying upon the various insects are the mud-dauber 

 wasp (Scelipron cementarius] and the digger-wasp (Ammophila nigricans}. 

 Parasites, such as Ichneumon zebratus, Paniscus gemminatus, Epeolus 

 cressonii, etc., occur upon the plants, and certain of them are often 

 found engaged in depositing eggs in or on caterpillars. The onion-fly 

 (Tritoxa flexa) (190) is striking because of its black body and black 

 wings, obliquely marked with white. 



Spiders, especially crab spiders, are abundant. The white Misumena 

 vatia occurs on the milkweed and the flowers of the mint. Epeira 

 trivittata and the long-bodied spider (Tetragnatha labor iosa} occur on the 

 blossoms and stems of various plants. 



