230 NEBRASKA STATE HORTICULTURAL SOCIETY 



or three inches below the surface, requiring about two weeks for this 

 task. On the average three weeks are spent as larvae in this pupal 

 cell, during which period the larvae undergoes marked structural 

 changes and is extremelj' helpless and delicate, this rinally resulting 

 in the formation of the pupa, equally helpless and delicate. Pupas 

 begins to occur the second week in June and continue to be present 

 in the soil until the end of July. The pupal period lasts from twelve to 

 twenty-one days with an average of seventeen days. Even after the pupa 

 has transformed to the beetle stage, several days are spent in the 

 pupal cell before the beetle ventures above ground. In two to seven 

 days, with an average of four days, the soft, yellowish, freshly trans- 

 formed beetle has hardened and assumed its normal, color and is 

 ready to leave the cell. After two or three days of digging the beetle 

 reaches the surface of the soil, and makes its way out. 



The emergence of the beetle begins the last few dayc in June, 

 reaches a maximum the second week in July, and gradually falls 

 off until the end of that month the beetleo have practically all emerged 

 The beetles are about a quarter of an inch lo ig and are covered 

 with very short, grayish hairs so as to appear hoary in color. In 

 looser, more porous, sandy or loamy soils the emergence is somevv-hat 

 earlier than in heavy, compact, c!ay soil, sometimes as much as a 

 week earlier, and in hillside vineyards the emergence is usually later 

 than in valley vineyards. The beetles quickly seek out the grape leaves 

 and feed upon them, causing the injury already described. Within a 

 few days after emergence mating begins, and from nine to twenty- 

 four days afier emergence, with an average of about sixteen days, 

 (.he female beetles begin their egg laying. They Hrst cease feeding 

 and become somewhat sluggish, locate on the canes and then "oy 

 means of the protrusible evipositor the females lay their eggs under 

 the loose bark of the canes and trunk of the grape. The eggs are laid 

 in clusters of about twenty-five to thirty-five individual eggs, but 

 sometimes there are as many as sixty or as few as four in a cluster. 

 These clusters having the individual eggs glued together and the 

 clusters as a whole glued to the bark or wood by means of an adhesive 

 secretion. At average intervals of four days the female deposits such 

 a cluster, until on the average four or five, but sometimes as many 

 as nine, of such clusters are laid. The average number of eggs laid 

 by this insect is about one hundred and twelve, but as few as fourteen 

 or as many as two hunderd and sixty-three may be laid, this depend- 

 ing upon the vitality of the individual female insect. Egg-laying 

 begins early in July and continues until latter September, but the 

 bulk of the eggs, practically three-fourths of them, are laid during 

 the last ten days in July and the first week in August. The individual 

 beetle lives on the average about a month, but some individuals may 

 live for twice that period of time. 



The hatching period of the eggs is from ten to twenty-four days, 

 but on the average is about twelve days. On hatching, the little 



