72 llississljJpi Valley Ilortieullural Society. 



the early observations of Prof. Riley, and to some contributions to the sub- 

 ject which I have been able to make since last August. 



The eggs are laid on the crown in spring (this year certainly not ear- 

 lier than April), being pushed down among the bases of the leaves. The lar- 

 va? penetrate the crowns soon after hatching, and excavate the interior all 

 summer, until they get their growth. 



It is worthy of note, however, that a single larva does not wholly destroy a 

 plant, as it matures by the time a quarter or a fourth of the substance of the 

 crown is devoured. (See Fig. 14.) Frequently two or three or more beetles will 

 att4ick a single stool, and they then leave behind them only a hollow shell, to 

 which the roots are attached. (See Fig. 15.) Still in its subterranean cavity, 

 the worm transforms to a pupa, and in the same safe retreat effects also the 

 final change into the mature beetle, this last transformation occurring all the 

 way along from August to October, during a period of about two months. 

 These beetles all escape from the crowns in autumn, but are not known to 

 lay any eggs until the following year. That they pass the winter as adults, 

 in the fields infested by them as larvae, I have proven by finding a number of 

 them there a'ive this year as late as November 29, and also by finding them 

 in the fields this spring. None of these insects, in any stage, occur in the 

 crowns later than the latter part of October, and none were to be found 

 there in Southern Illinois as late as April 25, although the adult beetles of 

 last year's brood were occasionallj- encountered on the crown among the leaf 

 stalks and leaves. A pair of these were seen there in copido, on the 12th of 

 that month. 



This is a shy and sluggish insect, rarely seen outside its burrow, and incapa- 

 ble of flight, the membranous wings being reduced to useless rudiments, as 

 shown by several dissections which I made last fall. As it does not leave 

 the field in which it had its origin, it feeds of course, while a mature insect, 

 on the tissues of the plant. 



The effect of this borer varies according to the variety of strawberry, and 

 the condition of the field. Wilsons are said to be destroyed by a single at- 

 tack, but some more thriftily-growing varieties will form new crowns year 

 after year to replace those excavated by the borer, and will thus resist its in- 

 juries for some time. Our observations show that this process is consider- 

 ably facilitated by hilling up the plants, or throwing dirt against the rows. 



I do not know that this insect has been found injurious anywhere except 

 in Illinois and Missouri, although we have specimens collected in Minnesota. 

 It doub'Jess originated in the wild strawberries of our prairies, and its work 

 could probably have been foreseen, and its ravages prevented, if a proper 

 study had been made, in time, of insect injuries to the wild plant. 



As these beetles spand their entire time in the field, and feed, of course, as 

 adults, up)n the foliage of the strawberry, it is not impossible that they 

 might be poisoned in tha fall. Except by this method, it is difficult to see 

 how the insect can be destroyed without sacrificing the plants. To kill both 

 together, the ground should b3 plowed late in June or early in July, when 

 the crowns are full of half-grown larvae. 



