Studies of the Development of Fidia viticida Walsh. 165 



and adults are abroad in very limited numbers the first week 

 in September. It fs probable that these were delayed indi- 

 viduals, the result of larvae which did not fully mature the 

 previous Autumn. On pupating, the larval skin is pushed 

 off posteriorly, and may be found in a compact disc in the 

 earthen cells, after the adults have emerged. A very few 

 pupae may be observed as earl} 7 as the first week in June, and 

 by the 23d fully ninety per cent, of the larvae have passed 

 into this stage, the period of which is not far from a fort- 

 night. At this date, the adults begin to appear, and pairing 

 at once commences, both sexes now feeding on the lower 

 leaves, though, later in the season, they are found higher up 

 on the youngest and most tender foliage. The feeding is done 

 entirely upon the upper surface of the leaves, except where 

 the fruit is the object of attack, and is done by gathering a 

 quantity of the substance of the leaf in the mandibles and 

 jerking the head upward, after which the body is moved a 

 step forward and another mouthful of food secured as before. 

 After securing a few mouthfuls in this way, they move to 

 another place and begin again, thus eating out numerous 

 chain-like areas of irregular length, as shown in Fig. 3, Plate 

 IX. On varieties of the grape having a velvet) 7 under-surface 

 to the leaves they eat only to the lower epidermis, on others, 

 entirely through the leaf. When alarmed, they usually draw 

 up the legs and fall to the ground, where they are not easily 

 distinguishable from the soil ; if however, the}' do not drop 

 at first alarm, or during a high wind, they will probably pay 

 no attention to almost any amount of disturbance, and can be 

 readily caught with the fingers. In the insectary, adults lived 

 upward of two months, though, in the vineyard, they have 

 mostly disappeared by August 1. 



It would seem that an insect whose larvae fed upon the 

 roots of their mutual food-plant would place its eggs in a 

 position most convenient for the young to reach their suste- 

 nance, but in this almost the contrary seems to be the case, 

 as the eggs are deposited in or under the bark of the previous 

 years, or even an older growth, and often several feet above 

 and beyond the roots, and the young larvae, whose feet are 

 not fitted for walking on vertical or steeply inclined surfaces, 

 tumble to the ground and find their way to the roots as best 



