576 Grasses and Leguminous Crops in New York 



with a sticky substance secreted by special glands and the fluid 

 is then mixed with air and worked into a frothy mass by a pair of 

 appendages at the tip of the body. The frothy mass is supposed 

 to serve as a protection for the insect against its enemies. While 

 these curious spittle insects often attract attention and provoke 

 inquiry they really do very little harm and remedial measures are 

 not necessary. 



TIMOTHY JOINT WORM 



Isosoma species 



If one splits a timothy culm lengthwise he is likely to find a 

 small white larva one-twelfth inch in length lying in the central 



cavity just above one of the lower 

 nodes (Fig. 619). Sometimes the 

 infested stems are slightly 

 dwarfed but more often they are 

 the largest and rankest arising 

 from the stool. The insect really 

 does not injure the hay crop to 

 any appreciable extent. Timothy 

 grass along fences and in waste 

 places is more liable to infesta- 

 tion ; one-year-old seeding is in- 

 fested only to a slight extent. 



The insect winters in the larval 

 state either in grass stems left 

 along the edge of the field or those 

 cut for hay. The insect trans- 

 forms to a pupa in the stem in 

 May and the small, black, four- 

 winged flies emerge the last of the 

 month. The -female fly inserts 

 her eggs in the tender stems of 

 the growing timothy plants and 

 the young larvae feed on the pith 

 just above a joint. There is only one brood annually. 

 No remedial measures are necessary. 



\ 



Fig. (il9. Timothy Joi.nt-VVorm 



In Its Burrow in a Grass 



Stem, Greatly Enlarged. 



