"The 3'oung seek a more protected place in which to feed, and 

 may be found in large numbers within nearly every sheath of June 

 grass during the latter part of May and through June. A favorite 

 haunt is in the head, just as it is making its appearance. The 

 minute young work their way down inside the sheath, and some of 

 them, reaching a node where they must stop, continue to feed upon 

 the juices from the very tender stem within until shortly before they 

 enter the pupal stage. The young may be found within any sheath ; 

 but it isTllmost always those that enter the top sheath which cause 

 the ' silver-top,' as these directly cut off the supply of sap to the 

 head. Examination of affected stems shows that at a point just 

 above the upper node the stem has been sucked dry for about half 

 an inch of its length (Fig. 6)." 



FOOD PLANTS. 



"This minute pest attacks a number of species of grass, but by far 

 the greatest damage is done to June grass (Figs. 5 and 6), few 

 fields of this escaping more or less serious injury. After the first of 

 July, by which time June grass has usually matured, the insect 

 changes to some later species, as timothy when this is present. 

 They may be found in abundance upon barn-yard grass from mid- 

 summer till late in the fall. About the middle of July, 1S98, 1 found 

 them quite common upon a field of young corn which was nearly 

 surrounded by grass land, but later in the season they could not be 

 found upon the corn. Many other grasses show unmistakable-traces 

 of the work of thrips by their whitened heads, and a list of these, 

 with the percentage of 'silver-top,' estimated on June 29, 1898, is 

 given below ; but I cannot positively connect this species with all 

 the injury. 



" The percentages given were obtained by counting the injured and 

 uninjured heads upon a small area on which the damage appeared to 

 be of average severity. Slight traces of 'silver-top' are indicated 

 by a dash in the column of percentage." 



Fowl-meadow grass, Poa serotina, 30 



Poa nemoralis, 80 



Wire-grass, Poa compressa, 40 



Poa arachnifera^ 20 



Poa Fletcheri, 10 



Poa aquatica. 35 



