Chap. 6. 



INVERTEBRAL ANIMALS OF VERMONT. 



171 



TRANSFORMATION OF INSECTS. 



account of their appearing to be intersec- 

 ted, or divided into sections. Must j^. 

 sects are subject to several changes of 

 form and habit called metaviorphuses, and 

 in this consists their most remarkable pe- 

 culiarity. Tlieir existence is made up of 

 four principal stages, viz : the egg, the 

 larva, the clirysalis, and the perfect ani- 

 mal. Directed by instinct, tlie parent in- 

 sect is sure to deposit its eggs in the place 

 most favorable for the support of the 

 young, which arc in due time to be hatch- 

 ed from them. From these the larvae are 

 at length produced in the form of mag- 

 gots, worms, or caterpillars. In this state, 

 which is entirely dissimilar to the parent 

 in form and mode of life, they feed vora- 

 ciously and grow rapidly, often attaining 

 a weight and bulk much greater than that 

 of the perfect insect. At length they 

 cease to feed, become stationary and en- 

 cased in a shelly covering, whiclr is often 

 surrounded by a cocoon formed of silky 

 fibres. This is what is called the chrysa- 

 lis OT pupa. After remaining for a while 

 in this condition, the shell is burst and 

 throvi/n off, and the insect emerges in its 

 perfect state, usually provided with wings 

 and often exhibiting the most brilliant and 

 beautiful colors. In this state only is it 

 capable of propagating its species. But 

 it, in general, continues in this state 

 only a short period, just long enough to 

 lay its eggs and die. Most insects feed 

 much more sparingly in their perfect 

 than in their larva state, and some do not 

 feed at all in their perfect state. 



The Cocoon, of which the above is a 

 figure, was found on a pine plain in Bur- 

 lington, upon a small bush, as above rep- 

 resented, in March, 1840. The Cocoon 

 was composed of strong brown silk, and 

 measured 3.-5 inches in length and 1..5 in 

 thickness. After being kept about three 

 weeks, or till the 20th of April, in a warm 

 room, a large butterfly, of which the fol- 

 lowing is a figure, came out of it, by ma- 

 king an opening in the upper end. 



V 



/ ^' V ^ 



This Butterfly measured 1.7 inch in 

 lengtli, and the spread of its wings was 

 just G inches. The color of the body belts 

 on the abdomen and portions of the wings 

 was a dark brick-red. General color of 

 the wings different shades of brown beau- 

 tifully variegated with white, blue, and 

 violet. A roundish black spot, contain- 

 ing a lunated light blue spot near the ex- 

 tremity of each outer wing,&c. This indi- 

 vidual was a female, and ui the course of 

 tlie seven days which it lived it laid 

 about 200 eggs. 



On the 17th of August, 1840, a cater- 

 pillar was picked up in the door-yard, of 

 which the above is a figure, ft was 3.5 

 inches long and 0.75 inch in diameter. 

 Its color was light pea-green. Upon its 

 body were six rows of spines, two on each 

 side, which were blue and pointed, and 

 two on the back, the four anterior ones 

 terminated by balls of the size of small 

 pin-heads, which were red, and covered 

 with small black thorns ; all the rest yel- 

 low with black points. Being placed un- 

 der a glass vessel, it immediately com- 

 menced spinning, and, before the next 

 day, had completely enveloped itself in a 

 cocoon, precisely similar to the one above 

 described. This remained in a chamber 

 during the winter, and in the spring of 

 1841, we had from it another butterfly, 

 answering exactly to that figured above. 



These details are introduced merely to 

 illustrate the metamorphosis which in- 

 sects generally experience, and to show 

 the manner in which many of them are 

 preserved through the winter. Others, 

 however, pass the winter in the larva 

 state, in the ground, and still more are 

 preserved in the eog, while some live 

 through the winter in their perfect state. 



While much pains have been taken, 



