20 BULLETIN 808, U. S. DEPARTMENT OF AGRICULTURE. 



taken in Michigan and many in New York. It has been reared spar- 

 ingly in confinement, not being a very tractable species. It has never 

 been reared from any host other than Agropyron. 



This species forms galls in the stems. Some of the galls resemble 

 somewhat those of tritici, being placed in the walls of the stem ; others 

 resemble those made by vaginicola, occurring in the sheath surround- 

 ing the head. In the latter case the head does not appear at all. 

 (PL VI, B.) 



There is only one generation a year, and, as with the majority of 

 species, they pass the winter as larvae in the galls of the old plant 

 stems, pupate in the spring, and emerge as adults in May. The spe- 

 cies is normally thelyotokous, males rarely occurring. 



HARMOLITA AGROPYROPHILA Phillips and Emery. 



Harmolifa agropyropMIa (10, p. 450) is the only species, besides 

 grandis^ that has two generations a year. Singularly enough, Agro- 

 pyron is one of the few plants infested by Harmolita that produce 

 stems continuously throughout the growing season. The majority 

 of the other jointworm species would find it difficult to maintain two 

 generations a year on a single host unless they were dimorphic like 

 grandis and one generation developed in the very young plants. 



H. agropyropMla was collected first in 1904 by F. M. Webster. 

 Since that time it has been collected by various members of the 

 branch of Cereal and Forage Insect Investigations. The writer has 

 been rearing and observing this species since 1905, when he first dis- 

 covered that it has two generations in a year. The larvae inhabit the 

 center of the stem and may be found at any joint. 



The species has never been reared from any host other than 

 Agropyron although repeated attempts have been made to induce it 

 to live on other plants in confinement. There are two generations 

 a y^ar, the first generation emerging very early, during the last week 

 in April and the first week in May. It is one of the first species to 

 emerge. The second generation emerges the latter part of June and 

 the first week in July.^ The second generation deposits its eggs 

 (fig. 2, g) in the young tender stems, and as it is rather late in the 

 season these stems do not produce heads. 



HARMOLITA ELYMI French. 



This species was described as Isosoma elymi in 1882 by G. H. 

 French (6) , who reared it from Elymus americcmus from Carbondale, 

 111. The writer's attention was first attracted to it in 1908, when it 

 was learned that it occupied the center of the stem of Elymus sp. 



^ These dates apply to Richmond, Ind. 



