October, '13] WEISS: NEGATIVE GEOTROPISM 407 



hibernating quarters and during their breeding season early in the 

 spring. Thus, out of a hibernating mass collected March 9, 1913, at 

 Sulphur Springs, Benton Co., by F. D. Bailey, containing 367 individ- 

 uals, 344 were typically marked while only two were spotless. Out 

 of 552 individuals collected at Carlton, during March, 1913, 500 were 

 typically marked; only 5 were spotless. Out of 33 individuals found 

 under bands on seven year old cherry trees May 15, 1913, 30 were 

 spotless, 1 was typically marked. 



3. The fact that the two are found intergenerating should not affect 

 their specific status, for frequently intergeneration takes place in 

 nature between different species of Coccinellidse. 



NOTES ON THE NEGATIVE GEOTROPISM OF CORYTHUCA 



CILIATA SAY, ADALIA BIPUNCTATA LINN, COCCINELLA 9- 



NOTATA HBST AND MEGILLA FUSCILABRIS MULS. 



By Harry B. Weiss, New Brunswick, N. J. 



Corythuca ciliata Say. Upon placing hibernating specimens of this 

 "lace bug" in a glass cage in a warm room, their re-actions to gravity 

 were manifested in a rather curious way. When the temperature in 

 the cage rose sufficiently, all became active and possessed of a desire 

 to climb vertical surfaces. Small sticks placed vertically in the cage 

 were soon covered with individuals going up and those unable to gain 

 a foothold on the sticks, climbed upon the backs of others and made 

 their ascent in this manner, until the sticks were covered with one 

 seething mass of insects. 



Those on the bottom of the jar re-acted somewhat differently. 

 One individual meeting another, would climb upon its back and a third 

 happening along would climb upon the back of the second and a fourth 

 and fifth would do the same, until a regular tower of "lace bugs" was 

 formed. As a rule, when the sixth attempted to climb up, the tower 

 would sway, finally topple and all would come down. If the first hap- 

 pened to be resting at an angle on the edge of a piece of bark, the tower 

 would extend out over the edge in an extremely perilous position and 

 usually collapsed when the fourth attempted to climb out. 



In most of the cases, the last one up, would fly off in the same man- 

 ner that a "lady bird" walks upward on a twig, until the top is reached 

 and then flies off, provided it finds no plant lice. 



In the bottom of the ca.ge were several pieces of bark and the insects 

 always preferred walking on edges or ridges that pointed upward. 



This negative geotropic response took place in the dark as well as 

 in the light, provided the temperature was high enough. Rays of 



