STATK HORTICULTURAL SOCIETY. 



249 



Studded, the larger points being arranged in transverse rows, a row upon each of the 

 elevated ridges into which the segments are divided by imjiressed, slender, transverse 

 lines. In addition to these black points, a few pale dots or minute warts are more or 

 less perceptible, one appearing on each side of the middle of the back on the second 

 elevated ridge of each segment, another lower down on each side upon the fifth ridge, 

 and some others below these. But on each of the first three rings these pale dots are 

 arranged in a single transverse row, on the first elevated ridge three dots on each side 

 placed equidistant from each other. Along the middle of the back is a pale yellow 

 line, which is sometimes very faint, or visible only on the anterior rings. Low down 

 on each side is a row of dots of a brighter yellow color than the line on the back, one 

 on each segment, placed a little back of the breathing pore. The breathing pores are 

 small, broad, oval, dull white, inclosed in a black ring which is bordered with yellow, 

 this border being more broad on the fore side, and sometimes wanting on the hind side. 

 The head is spheroidal, and as broad as the neck, green, and clothed with hairs. The 

 legs and prolegs have the same green color as the body. 



Instead of commencing at the margin of the leaf and eating inward, 

 as is the habit of many leaf-eating insects, it riddles it with holes, grad- 

 ually enlarging these where the worms are numerous, until all that portion 

 between the veins is consumed. Although they will commence opera- 

 tions on either the upper or the under side of the leaf, yet my observa- 

 tions lead me to believe they prefer commencing on the upper side. 

 Although they bore into the incipient heads, yet I did not find this habit 

 so general as I supposed from what I had read in reference to them; 

 in fact I seldom found them making their way into well-formed, com- 

 pact heads. When the heads are forming, and they commence work 

 on the outer clasping leaf, this appears to have the effect to cause it to 

 partially open or withdraw from the head, which enables the worm to 

 work more freely. This also has a tendency to prevent the cabbage from 

 heading. 



Notwithstanding the butterfly appears to be aggressive in its nature, 

 in this country at least, driving away by its simple presence, or in some 

 other way, our native congeneric species, the larva, on the other hand, is 

 of a quiet and peaceful disposition, avoiding intrusion upon each other 

 and upon other insects. It is with much hesitancy it passes from its leaf 

 to another; and Dr. Fitch noticed that if an aphis was located on a leaf 

 near where the worm was feeding, the latter would, without encroaching 

 upon or in any way molesting, leave untouched a portion of the leaf a 

 half an inch or more in extent around the aphis. I have observed an 

 aphis walking freely over one of them without it making any effort to 

 disturb or cast it off. 



Although apparently so tender and delicate in its organization, it is 

 exceedingly tenacious of life; acrid substances which will readily destroy 

 many other caterpillars appear to have but little or no effect upon it. I 

 have noticed them eating away though covered with pulverized lime; Dr. 

 Fitch has observed the saine thing with reference to white hellebore, and 

 yet this will readily destroy the currant-worm or saw-fly larva. The same 

 author also states that on one occasion he found one frozen in a cake of 

 ice, which, after being thawed out, revived and completed its transforma- 

 tions. How it is possible for an insect apparently so tender, and com- 

 posed almost entirely of fluids, to survive under such a degree of cold, is 



