February-, '16] SOMES: SOI.ANUM INSECTS 41 



horse nettle and promptly began oviposition. The female clings to the 

 petiole of a leaf with the abdomen touching the main stem. The 

 slender and transparent ovipositor is extruded and the eggs are de- 

 posited singly or in grbups on the stem. The eggs are oblong ovate, 

 the upper surface broadly concave and the surface hexagonally ridged, 

 the ridges fainter on the concavity. The color at first is nearly white, 

 changing rapidly to a smoky black, the ventral surface remaining 

 lighter. From these scattered adults throughout the summer we must 

 assume a very irregular breeding period. In some of our experiments 

 early in September, several plants of the horse nettle were taken up, 

 together with squares of soil averaging about ten inches across. These 

 were then placed in cages and watched for emergences. In a couple 

 of days a male moth emerged from one of these squares. This was 

 placed in another cage with a newly emerged female. Within fifteen 

 minutes the pair were united, facing in opposite direction and re- 

 mained in copulation for about an hour. Later examination of the 

 plant in this cage revealed a total of 63 eggs attached to the stem and 

 under side of leaves. 



Transfers to Tomato and Potato. — To test the behavior of 

 larvae on other plants related to Solanum carolinense, we introduced 

 them on the stems of tomato, potato, Physalis puhescens L, and Sol- 

 anum nigrum L. The transfers were made by taking larvae from stems 

 of the horse nettle in June and placing them on stems of the desired 

 host plant at places which had been slit or punctured. In every case 

 they showed not the slightest hesitation, but promptly went to work 

 and were soon out of sight. One little fellow, which was not care- 

 fully placed, fell off to the soil below where he was noted wandering 

 aimlessly about twelve hours later but when placed in position again, 

 he had worked his way into the tissues within three hours. Varying 

 - numbers, from two to six larvae, were introduced into a eingle stem but 

 in no case where the stems were spilt and examined in late August 

 were more than two larvae found alive. The growth in both potato 

 and tomato and Physalis was perfectly normal and larvae taken from 

 these in August were vigorous and healthy and comparable in size 

 with those taken from field plants of the horse nettle. In the case of 

 Black Nightshade, Solanum nigrum L., however, every larva had died 

 and in most cases before it had bored over an inch. In tomato and 

 potato some borings were over eighteen inches long. 



Climatic Experiments. — Noting the superabundance of adults in 

 the fall of 1914, after a season of exceptional drought, we arranged a 

 series of cages to give a rough test as to the effect of seasonal conditions 

 on the growth of the larvae. The cages used were of galvanized iron, 

 16 by 16 by 20 inches. Those of Series A were open-screen cages of the 



