HYMENOPTERA 931 



hardened straw coming from the threshing machine with the grain. 

 There is but a single generation of this species in a year. The insect 

 remains in the straw and stubble during the winter, the adults emerg- 

 ing in the spring. The methods of control of this pest are rotation of 

 crops, burning or deep ploughing under of stubble when practicable, 

 or harvesting of stubble in spring with a horse-rake and burning it 

 before the adults emerge. 



The wheat straw-worm, HarmolUa grUndis. — This species is often 

 a serious pest of wheat west of the Mississippi River; it also occurs 

 in the East, but is rarely so injurious in this section as is the wheat 

 joint-worm. The adults differ from our other species of Harmolita 

 in that the mesonotum is smooth, polished, and shining. This species 

 also differs in that it exhibits a seasonal dimorphism. There is a 

 summer generation, which consists only of winged females, and a 

 winter and spring generation which consists of both males and females. 

 These are smaller than the summer form and are frequently wingless. 

 The adults of the winter and spring generations emerge in April and 

 the females deposit their eggs in the young wheat plants; the larvae 

 eat out and totally destroy the forming heads of wheat. The adults 

 of the second generation deposit their eggs, about the time the wheat 

 is heading, just above the youngest and most succulent joints which 

 are not so covered by the enfolding leaf-sheaths as to be inaccessible 

 to them. The larvae pupate by October and the winter is passed in 

 the straw or stubble. 



Seed-infesting Eurytomids. — Among the phytophagous members of 

 this subfamily are several species that infest seeds. The grape-seed 

 chalcid, Evoxysoma vliis, is common in the seeds of wild grapes and 

 occasionally infests cultivated varieties, which are injured by punc- 

 tures made by the females in ovipositing. The injured berries color 

 prematurely and sometimes shrivel and drop. 



Another species that is of economic importance is the clover-seed 

 chalcid, Bruchophagus funebris, which infests the seeds of red and 

 crimson clovers and alfalfa. This insect usually winters over in the 

 seed as a well-developed larva; the pupal stadium is rather short 

 and the adult lays her eggs in May and June. For an account of seed- 

 infesting chalcid-fiies see Crosby ('09). 



Subfamily TORYMIN^ 



This subfamily like the preceding one includes both parasitic and 

 phytophagous species. Many of the parasitic species prey upon gall- 

 making Lepidoptera and Diptera. Among the phytophagous species 

 are the apple-seed chalcid, Syntomdspis drupdruni, and various species 

 of Megastigmus, which infest the seeds of various plants. See Cros- 

 by (09). 



Subfamily AGAONIN^ 



The Fig-insects 



This subfamily is composed of those remarkable insects that live 

 within figs and fertilize them. It is represented in the United States 



