The life history, habits, and prey preferences of the orb weaving spider,Tetragnatha laboriosaHentz, were studied in central Illinois where this species is the most abundant foliage spider in soybean fields, comprising more than 60% of the total spider population during the summer months. Field and laboratory observations established that development from the egg to adult stage requires ca. 12 mo. There are 9 instars including the adult stage. Adults occur in undisturbed grassy areas adjacent to soybean fields. Males first appear in late May followed by females a week later. Males live an avg of 16 days while females live an avg of 21 days. Mating, oviposition and egg development are described. Three distinct courtship patterns were observed forT. laboriosa. Mating occurs in early June and the 1st instar spiderlings begin emerging 11 days later. By mid-June 2nd-instar spiderlings are dispersing into the fields by ballooning.Early instars spin their webs on the lower two-thirds of the soybean plant in the axillary region of the leaf or between the small trifoliolate leaves. As the spiderlings grow they construct webs progressively higher and toward the periphery of the plant. Web spinning reaches its peak from ca. ½ h before sunset until sunset. A new web is usually constructed each day near the old web site in 20–30 min. Growth continues throughout the summer months and the 5th and 6th instars are reached by early Oct. when growth slows down or ceases. Most individuals overwinter in the 5th or 6th instars. Growth resumes in the spring and continues until the adult stage is reached in late Mayor early June.Feeding in this species reaches its highest level from sunset to just after dark during the summer months. Prey consist predominantly of insects of the families Cicadellidae (Homoptera), Miridae (Hemiptera), Chironomidae and Drosophilidae (Diptera), and feeding is restricted to insects trapped in the web.