13 



were begun this season (1899) by confining hibernating females 

 in bottles before the weather became warm enough for them to 

 move out of doors. These became active and deposited eggs, 

 from which succeeding generations have been bred without the 

 appearance of any males. I conclude, therefore, that this species 

 is parthenogeuetic, and reproduces without the intervention of any 

 males, at least for a series of generations, in this locality. The 

 eggs may be seen in the abdomen before being laid, and I have 

 found as many as eight fully developed in a single female. 



Feeding Habits. 



The adults of this species feed entirely upon the leaves and ex- 

 ternal parts of the grass. They are very seldom found within the 

 sheath of a leaf, but frequently congregate in numbers within the 

 terminal leaf before it has fully unrolled. They select the fresh, 

 tender parts of the grass, and consequently their work is most 

 apparent upon the upper leaves. The mouth parts (Plate III., 

 figs. 19, 20, 21 and 22) are formed entirely for sucking. The 

 bristle-shaped mandible and the similarly formed lobes of the 

 maxillae are used to pierce the epidermis of the leaf and the wall 

 of a cell below. As soon as the juices contained in this cell have 

 been extracted, the piercing mouth parts are withdrawn and another 

 cell is punctured, the empty cells presenting a shrunken, whitish 

 appearance. The insects usually feed lengthwise of the leaves, 

 their path being marked by whitish streaks in the tissue of the leaf 

 and by dots of dark excrementitious matter. 



The larvse seek a more protected place in which to feed, and 

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

 grass (Poa 2)ratensis) 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 larvaa 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 larvas may 

 be found within any sheath ; but it is almost 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 (Plate I., 

 fig. 6). 



While I cannot state positively that this species is ever carniv- 

 orous, my observations have led me to suspect that such may some- 

 times be the case, though normally it is certainly herbivorous. I 



