10 



did not notice any conflicts in the open, we both experienced 

 the utmost difficulty in keeping the adults in sufficiently close 

 quarters to enable us to study their actions. If a male and 

 female were confined at all closely, they would instantly attack 

 each other with such ferocity that within a few moments they 

 would be rolling helplessly about among fragments of legs and 

 antennae, only the basal portions of these remaining attached 

 to their bodies. It was found wholly impossible to transport 

 living individuals without giving them ample quarters, and I 

 was finally forced to give each a box or vial to itself. 



The other peculiarity referred to is alack or insufficiency of 

 the dispersal instinct when the beetles become excessively 

 abundant in a locality. Though no trace of them was found 

 in some parts of the city of Decatur, in other parts they were 

 so abundant that the young growth of the elm did not afford 

 them sufficient material in which to mature more than a small 

 percentage of their larvae, only one of which can develop in a 

 single twig, but instead of hunting for other trees where suit- 

 able conditions existed, the females girdled the twigs and de- 

 posited the egg where this had been done, not only once, but 

 time and time again, before. I have found twigs in which 

 there had been as many as eight separate ovipositions, with the 

 usual number of girdlings in each case. 



The upper figure in the colored plate affords a very good 

 illustration of a multiplicity of ovipositions, as also one of 

 the twigs in the cluster below. We have here, consequently, 

 what might almost be termed insect infanticide on a stupen- 

 dous scale. But the full extent of this wholesale murder does 

 not appear in the illustrations. In all examinations of the am- 

 putated portions of the twigs made by Mr. Titus, he found none 

 which contained eggs or larvae, and this was true of my own ob- 

 servations, made during the early part of the egg-laying season. 

 Late in May, however, I began to find sections of amputated 

 twigs on the ground underneath the trees, which showed plainly 

 that this amputation was not the result of a first visit of a female 

 intent on oviposition. Ordinarily, the tip of the twig is severed far 



