22 PSYCHE [April 



One or more pairs of beetles may be kept in a single dish. A few fresh leaves of 

 willow or rose were placed in each dish every morning and the partly eaten leaves of 

 the previous day removed. 



Eggs were collected at various times, usually in the morning unless the exact 

 time of laying was desired when the dishes were examined every hour throughout the 

 day. They are laid in batches on the side of the leaf which is beneath. The part 

 of the leaf to which the eggs were attached was cut out and placed in a watch glass. 

 A water soaked piece of filter paper was included to prevent desiccation. If kept too 

 moist a fungus, one of the mucors, attacks the eggs. The eggs remained in the watch 

 glass until they hatched. 



The larvae were placed in small dishes and fresh food was given them every day 

 as in the case of the adults. When the larvae were nearly ready for pupation they 

 were transferred to dishes containing an inch of sandy loam. They burrowed into 

 this and formed a spherical chamber in which they lay on their backs while their last 

 larval skin was shed and during the pupal period. The imagos escaped to the sur- 

 face immediately after being freed from their pupal covering and before their color 

 pattern had made its appearance. 



Egg-laying in C. miiliipvnctata will answer for that of the three species under con- 

 sideration as there was no appreciable variation in time, number, or method. A 

 number of beetles were examined while laying, the process being as follows. The 

 beetle selects a leaf and clings to its under surface. The tip of the abdomen moves 

 rhythmically up and down about fifteen times at intervals of a little less than one sec- 

 ond. This results in the exudation of a drop of viscid colorless fluid about one third 

 the transverse diameter of the egg. The egg is forced out a moment later and car- 

 ries with it this drop of fluid by means of which it is fastened to the leaf. When the 

 egg reaches the leaf it is pushed back away from the beetle which then moves to one 

 side and begins the rhythmical movements which precede the laying of another egg. 

 In this way eggs are laid in a double row as shown in the accompanying figure, but 

 frequently three or more may be laid in one row. The intervals between the layings 

 of the individual eggs average one minute and twenty seconds. 



Fifty-four pairs of beetles were examined daily during the laying period and a 

 record made of the number of eggs laid. One pair })roduced fourteen eggs on June 

 fifteenth and a batch was laid every day with the exception of several longer intervals 

 until August twenty-seventh. Two to nineteen were laid at one time, the largest 

 number for any one day being twenty-nine and the average number per batch, eight. 

 The total number laid by this pair w^as three hundred and seventy-six in seventy-four 

 days. Other pairs produced eggs as follows: 2S1 between June 22 and Aug. 3, 38 



