6 BEXLETIX 834, U. S. DEPABTMEXT OF AGBICTTLTUKE. 



Triticum repens, Broinus, Holcus, and reeds or bulrushes, without 

 specifying which plants serve as host plants for the different species. 

 The record is, therefore, too general to be of much value in the 

 present circumstances. 



The Russian records are more specific and apparently all refer 

 to infestation of small-grain crops. Shtchegolev (49) records the 

 species as a serious pest of wheat; Borodin (52) reared it together 

 with Cephus pygmaeus from barley and both spring sown and 

 winter sown wheat ; Kulagin (47) states that it infests rye and wheat 

 in the Province of Taurida. Various other Russian writers, includ- 

 ing Uvarov (50) (54), Zolotarevsky (53). and Kurd jiunov (48), have 

 recorded the species as attacking the grain crops, principally wheat. 



FOOD PLANTS IN AMERICA. 



Thus far in America only wheat and rye are known to serve as 

 food plants. Only two instances of its occurrence in rye are known, 

 both observations having been made by the writer during the past 

 summer. In each instance in which it was found in rye only one 

 infested stalk was located in the field, although careful search was 

 made. Although several fields of oats stubble were examined more 

 or less carefully, no infestation of this crop was observed even when 

 the oats were in close proximity to infested wheat fields. Xo oppor- 

 tunity to examine barley has offered itself. 



It appears fairly certain that of the cultivated grain crops wheat 

 will prove to be its preferred food plant. As stated elsewhere, the 

 writer was able to find larvse in varying quantities in every wheat 

 field visited in the course of the limited investigation carried on 

 during the summer of 1918. 



That the species eventually will be found to infest plants other 

 than the small grains is possible. The related species, Cephus 

 cinetus, which also infests the small-grain crops in our TTestern 

 States, is known to have a long list of food plants among the coarser 

 grasses, both wild and cultivated. Cephus cinctus is believed, how- 

 ever, to be a native species whose original food plants were wild 

 grasses and whose habit of attacking the cultivated grains has been 

 induced through elimination or reduction of its natural source of 

 food supply by the development of agriculture. Present informa- 

 tion indicates that the natural food plants of Trachelus tahidus are 

 the small grains, although it may yet prove to have other hosts in 

 Europe. It is doubtful whether the species which has been trans- 

 planted from its native habitat to America will find it possible to 

 develop in our native grasses. Only future investigation can de- 

 termine. The possibility of its being able to maintain itself upon 

 grasses other than the small grains should be borne in mind, and 



