in length, many of which do not go over with the straw and cliaff , 

 but remain with the grain. The presence of these bits of broken straw 

 in the grain is frequently the first evidence the farmer has seen of the 

 occurrence of the pest in his fields. Millers and elevator men note 

 them also, and in sections where the pest has committed serious dep- 

 redations several bushels of these hardened bits of straw are found 

 after each day's cleaning of the grain. 



EFFECTS ON THE KERNEL. 



The wheat heads from infested stems are foreshortened, and the 

 kernels thereby necessarily reduced in both size and number, and in 

 case of severe attack they become shrunken. 



NATURAL ENEMIES, 



Natural enemies of the joint- worm are quite numerous, and 

 most of them have the advantage of being double-brooded, whereas 



the joint- worm has but one generation 

 annually. 



Among the most efficient of these are 

 two rather common species of insects. 

 One of these, almost as big as the Isosoma 

 itself, with dull metallic thorax and yel- 

 low abdomen and with long ovipositor, 

 is Ditropinotus aureoviridis Crawford, and 

 the other, smaller, darker colored, and 

 slender, also somewhat resembling an 

 Isosoma, is Eupehnus allynii French. 

 The \\Titer reared also another species in 

 Ohio, Wehsterellus tritici Ashm.., which has 

 similar habits. 



A somewhat similar insect %vith metal- 

 lic body and A^ellow abdomen, Stictonotus 

 isoso m a tis Riley , is very efficient in destroy- 

 ing the larv?e in the straw. Homoporus 

 (SemioteUus) chakidiphagus Walsh and 

 Riley, and beyond a doubt other chalcidoids, are also instrumental in 

 holding the pest in check. These are all small four-winged flies, and 

 a number of additional, undescribed forms have been discovered. 



The larva of a small, slender, black and yellow carabid beetle (Lepto- 

 trachelus dorsalis Fab.) crawls up, descends into the stubble, and de- 

 vours the Isosoma larvae, but unfortunately its sense of taste seems to 

 be too obtuse to allow it to confine itself strictly to Isosoma, and as a 

 consequence it devours parasites as well as host. A mite, Pedicu- 

 loides (Iletoropus) ventricosus Newp., is also an enemy, gaining access 

 to the larvie precisely as does the beetle larva pre^dously mentioned. 



[Cir. 00] 



Fig. 5. — Bits of hardened straw re 

 maining with the grain after thrash 

 ing. (Author's illustration.) 



