June-Sepl. 1894.' 



PSYCHE. 



133 



As late as August 19th there was one 

 caterpillar whose length was only one inch. 

 It had moulted but twice: and, as its mouth 

 parts seemed to be defective, it was put into 

 alcohol. The number was thus reduced to 

 nineteen. 



On August 22ud the first cocoon was 

 begun in a corner of the box, and on the 

 23rd and 24th two other corners w-ere uti- 

 lized in tlie same way. After this the 

 remaining caterpillars were removed from 

 the box as fast as they were read_v to spin, 

 and placed under more favorable conditions. 



Two spinning places were provided. The 

 first consisted of small branches of an apple- 

 tree standing in the sockets of a board, the 

 whole enclosed in cotton netting. In the 

 other the branches stood in a pitcher of water, 

 the mouth of the pitcher being covered with 

 paper to prevent death by drowning. These 

 branches were not enclosed in any covering, 

 but in no case did the caterpillars tr3' to wan- 

 der away. 



In selecting a place for its cocoon the cater- 

 pillar, holding to the twig by its anal feet, 

 sought, by reaching out in all directions to 

 the full length of its body, to find points of 

 attachment for what may be called its guy- 

 ropes. The spinning of these was done very 

 deliberately and occupied several hours. 

 When the cocoon had been roughly shaped out 

 tlie caterpillar rested for three or four hours, 

 its work afterwards progressing rapidly. 



All the caterpillars enclosed by netting 

 made use of it in beginning their cocoons, 

 while the others used the leaves and paper 

 within their reach; so that many of the 

 cocoons were partly concealed by a covering 

 of foreign substance. In one instance three 

 were grouped close together, and eightothers 

 were arranged in pairs. 



Irr some cases the silk, when first spun, was 

 beautifully white and lustrous, changing after 

 exposure to the air to a rich reddish brown; 

 in others it had a brown tinge from the first. 



It has already been stated that two of the 

 full-fed caterpillars died. One of them spun 



a few threads on .\ugust 30th, and for the 

 remaining four days of its life went tlirough 

 all the motions of attaching threads but with- 

 out producing any more. The other died on 

 the second day after it had selected a place for 

 its cocoon. It produced no silk at all. 



The cocoons were collected, put into a 

 pasteboard box, and kept in a cold, dark closet 

 until April loth, when they were taken into 

 a warm room. A cage was made bv en- 

 closing a small, deep-seated nortlj window 

 with netting, and the cocoons were pinned to 

 the window franje. The glass itself was cov- 

 ered with netting stretched tightly over it. 



During a period of nineteen days beginning 

 May 24th, sixteen inoths emerged, seven 

 being males, and nine females. Two of them 

 did not succeed in fully expanding their 

 wings; the others w-ere perfect insects. 

 The seventeenth cocoon was found to contain 

 only a dead caterpillar. 



A few of the moths were given the freedom 

 of the cage for several days, in the course of 

 which five hundred and ten eggs were laid 

 by two females, one depositing two hundred 

 and forty-six, the other two hundred and 

 sixty-four. A majority of the eggs hatched. 



It will be seen that the conditions under 

 which these moths were reared difter in 

 several respects from the conditions con- 

 sidered essential by some entomologists, 

 who say that the larvae should be kept in 

 a datnp cellar up to the time of the first 

 moult; that not more than two or three 

 should live in the same cage for fear of 

 contagious disease; and that the atmospliere 

 in which the cocoons are kept through the 

 winter should be moist as well as cold. 



My experience is not suflicient to enable 

 me to decide whether my larvae escaped 

 death merely by a happy chance, or whether 

 the conditions just quoted are non-essential 

 in all cases. I am inclined, howevej'. to 

 the latter opinion, in view of the many 

 unsuccessful attempts to rear the larvae 

 even when those conditions have been 

 complied with. 



