34 THE SUGAR-BEET WIREWORM. 



bet'tlos may bo found side by side. Now and then, about the middle 

 or latter part of April, a beetle is seen sunning itself at the edge of 

 a beet under which it had been hiding. At about this time, also, it 

 was noted that the underside of many of the beets which sheltered 

 beetles was roughened and had the appearance of being shredded. At 

 first no attention was paid to this until by chance a beetle was noted 

 feeding on an old beet, and then it was seen that the roughened 

 places on the beet were the feeding marks of the adults. "N'NTienever 

 a beet was turned over the beetles were for the most part active 

 (PI. XVII, fig. 2), but a few were still in their secondary hibernation 

 (PI. XVII, fig. 1). The feeding marks on the beets become more 

 and more noticeable but are never especially extensive, as the adults 

 at the period of their greatest activity are light feeders. 



Even at this time the beetles are not entirely normal in theu" 

 actions. This is most noticeable in regard to the habit of feigning 

 death, so characteristic of most of the elaterids. AMien a group is 

 exposed by remoAdng the beet under which they have been hiding, 

 at least half of them move about searching for shelter. This is 

 probably due to the fact that their senses are not very acute at this 

 time, and they consider only shelter. About a month later, however, 

 when a group of beetles is exposed by removing the beet shelter, 

 most of them remain quiet for some time, even though they may 

 happen to be in an imusual position. 



VARIATION IN THE SIZE OF BEETLES. 



Among the beetles taken in the field there was a very noticc^ablc 

 variation in size. (See PI. I.) The length was often foinul to vary 

 between 9 and 12.2 mm., and the width between 2.5 and 3.5 mm. 

 The larger ones outnumbered the smaller ones almost 2 to 1, since 

 about 15,000 of those collected could be referred to the larger size 

 to about 9,000 of the smaller, while about 2,000 or 3,000 were so 

 nearly on the dividing line between the other two sizes that they 

 were unclassifitnl. At first the large ones were thought to be females 

 and the small ones males, so it was concluded that the fc^males out- 

 numbered the males about 2 to 1 . Such did not prove to be entirely 

 the case, for when copulation became general some of the small ones 

 proA^ed to be females, and not a few of the larger ones were seen to 

 be males. Everything considered, it seems that sex is quite inde- 

 pendent of size, for the males and females were seen to occur in about 

 equal numbers. 



VARIATION IN THE COLOR OF BEETLES. 



From the outset it was noted that there was great variation in 

 the color of the beetles. This difference was most notic(^able on the 

 elytra, which varied from light bufl' to deep brown or dusky black. 



