Report of the State Entomologist. 



153 



river banks, meadows, and rich shaded woods of the Southern and 

 Western States, and sometimes known as "wild rye." 



Isosoma vitis Saunders,* known as the "grape- 

 seed insect," the larva of which, represented in 

 natural size and in enlargement in Figure 13, feeds 

 within the Seeds of grapes before the ripening, 

 causiuer the fruit to shrivel and fail of maturing. 



Fig. 13.— Larva of the 

 grape-seed midge, 



ISOSOMA YITIS. 



Remedies. 



It is fortunate that we have at our command means for controlling 

 the depredations of this insect, which are simple, easy, and 

 inexpensive. 



Since its entire life, from its hatching to its emerging in its perfect 

 state, is passed within the straw and in quite a limited locality 

 therein, it is evident that if the straw be destroyed by burning, or by 

 any other as effectual a method, at any time prior to the emerging of 

 the winged insect, the entire brood will be destroyed with it. 



If the grain is not cut unusually close, a large proportion of the' 

 larvse will be left in the stubble 

 The stubble of an infested field 

 should be burned over at any 

 convenient time favorable for 

 the burning. There is not the 

 objection to this expedient in 

 this case, that may properly be 

 urged against burning for the 

 Hessian fly — that it destroys 

 the many parasites which ren- 

 der such excellent service in reducing its numbers — for the known 

 parasites of the joint-worm are but few, and thus far they have proved 

 of but little value in its reduction. Dr. Harris has justly remarked: 

 " We need not be restrained by the consideration that the, diseased 

 straw contains also some truly parasitical larvse ; for these are very 

 few in number compared with the immense swarms of the Uurytoma 

 [Isosoma] that are annually produced. If we can succeed in exter- 

 minating these destroyers, we shall have no occasion for the services 

 of the parasites." In figure 14, its principal parasite, Semiotellus 

 chalcidiphagus Walsh, is figured in both sexes. Eupelmus Allynii 

 (French) is also parasitic upon it, but to a much more limited extent. 



It is believed that a deep plowing under of the infested stubble 



* Canadian Entomologist, ii, 1869, pp. 25-27. Country Gentleman, for September 21, 1876, 

 xli, Pi 599. Entomological Contributions, iv [Lintner] 1878, pp. 24-28. 



20 



Fig. 14.— Joint-worm Parasite, Semiotellus 

 CHALCIDIPHAGUS — female and male. 



