PSYCHE. 



[January igoo. 



even space to turn over completely. 

 The walls of the cavit)' seemed pressed 

 by the turning of the caterpillar and 

 moistened by the sticky fluid vvliich 

 exudes from such larvae in the early 

 stages of pupation. This combined 

 fluid and pressure served to keep the 

 earth from falling upon the caterpillar 

 under ordinary circumstances, but a 

 very slight touch with pencil, fingers, 

 or stem sent the upper walls down as 

 dirt, not as fragments of a case or of a 

 wall. 



I then put less earth in a tin anti put 

 on it a caterpillar which was ready to 

 burrow, and watched it. 



Butting its head against the earth it 

 made a small iiole, then worked the 

 hole larger until it would admit the 

 entire body, which the earth was not 

 deep enough to cover. 



The caterpillar then moved about in 

 this hole, butting the sides with its head 

 ■ until there was room to spare, and the 

 walls were packed \)y the pressure. 

 Exudation had begun and the fluid was 

 forced against the walls by the crawling 

 and butting of the caterpillar, so that 

 all was absorbed by the earth. 



There was no spinning whatever, 

 nor any of the weaving motion of the 

 head made by the caterpillar when 

 spinning. At first the caterpillar lay 

 on its venter, shortened and moist. 

 After a daj' or two it turned upon one 

 side, curled slightly in a curve. Next 

 it turned on the other side, then on its 

 back, still slightly curled. Then the 

 ends of the skin began to look empty, 

 and the caterpibar slowly rolled over 



upon the venter, and soon cast the larva 

 skin. I repeated this experiment sev- 

 eral times, and with diflerent species, 

 and always with the same result. 



Uryocamfa rubicimda gave the 

 same results also, though much less 

 fluid exudes from these. 



I satisfied myself that with these 

 species the cell formed for pupation 

 could not be called either a case or a 

 cocoon, since it could not be taken up 

 as a whole without taking up enough of 

 the surrounding earth to keep from it all 

 pressure and jar, as these destroy it at 

 once. 



I tried the same plan with Dcilepliila 

 llncata, which in my former experiences 

 has always spun a slight cocoon, like a 

 fish-net, between leaves. 



The four sj^ecimens I put into the 

 four tins with earth, shaped cells for 

 themselves, and did not spin at all. 

 They did not burrow as deep as the 

 other larvae however. 



The boxes were kept tightly covered 

 except when I was watching the cater- 

 pillars, so that the earth v\as not dried 

 too much. 



The pupae were all perfect, but no 

 better, except those of the Protoparce 

 and C. ajJiy)itor, than those made by 

 the other larvae pupating in tins with- 

 out earth. 



In making their cells the caterpillars 

 did not bring earth to the surface, but 

 merely pushed it back on all sides, so 

 that in the tins with deeper earth there 

 was no trace of any buirow or cater- 

 pillar. 



