JOINTWORM FLIES. 19 



LIFE HISTOEY. 



As this grass grows naturally in waste places and along fences its 

 jointworm enemy does not depend upon cultivated areas to maintain 

 itself. It winters in the old seed stalks as pupa, the adult emerging 

 near the middle of May. The species is normally thelyotokous, 

 males very rarely occurring. 



SPECIES INFESTING WILD GRASSES. 



In the preceding pages the writer has given briefly some of the 

 more important facts relating to all the species at present known to 

 infest our grains and cultivated grasses. It may appear at first 

 glance that wheat has rather more than its share of species, especially 

 since it is our most important small grain. On the other hand, the 

 genus El3^mus, a wild grass, is the home of nine species, eight of which 

 are gall-formers; Agropyron sp., another wild grass, has four species, 

 three of which are gall-formers. The species infesting the wild 

 grasses will be dealt with very briefly. A good many of them may 

 lay a just claim to some consideration from an economic standpoint, 

 from the fact, as previously stated, that they have parasites in com- 

 mon with the more important economic species. 



HARMOLITA MACULATA Howard. 



Howard (8, p. 15) described this species as Isosoma Tnaculatum 

 in 1896 but nothing was known then of its life history. In re- 

 cent years it has been collected by various members of the branch of 

 Cereal and Forage Insect Investigations. The writer has reared it in 

 confinement since 1912. It has persistently refused to breed in any 

 host other than grasses of the genus Bromus. It does not form galls 

 but lives in the walls of the plant stem, particularly of cheat {Bromus 

 secalinus). The cheat stem is almost solid near the base, at least just 

 above the lower joints, the walls being very thick. The Qgg (fig. 8, d) 

 apparently is deposited in the walls of the stem somewhat like the Qgg 

 of tritici and the larva excavates a little tunnel about half an inch 

 long just above the joint (PI. V, B). There are sometimes two or 

 three to ^an internode. It is a very widespread species and un- 

 doubtedly occurs wherever cheat or other species of Bromus are 

 found. 



There is only one generation a year. The species hibernates in 

 the larval stage, pupates in the spring, and the adults emerge in May. 

 It is arrhenotokous under control conditions though in nature both 

 sexes occur. 



HARMOLITA ATLANTICA Phillips and Emery. 



Harmolita atlantlca (10, p. 461) is a species which the writer first 

 reared near Eichmond, Ind., in 1909. A few specimens have been 



