340 MISSES K. FOOT AND E. C. STROBELL : RESULTS OF 



cage for the nymphs, care being taken to select a size deep enough for the 

 food and large enough to hold from 20 to 30 nymphs without orercrowding. 

 Sometimes as many as 30 nymphs are Latched from a single batch of eggs, 

 and these mav be very active after the first moult. We selected wet 

 chamber dishes, about 120 mm. in diameter and 25 mm. deep. Experiments 

 proved that the nymphs have sufficient air in these dishes, and can be raised 

 with safety through the five moults to the winged stage. 



The food suitable for the adult bugs is not satisfactory for the larval 

 stages. Until after the third moult the nymphs are so small that they hide 

 under the petals of the berries and in the grasses, and it requires too much 

 time and patience to find them. The most satisfactory food for these stages 

 proved to be the small, tender leaves that form the centre of headed lettuce. 

 Experiment showed that the nymphs often select these leaves in preference 

 to the berries, and they certainly develop most satisfactorily on this food, 

 through the five moults to the winged stage. During the height of the 

 breeding season we used 15 heads of lettuce a day, as the nymphs were 

 transferred to a clean cage and fresh lettuce every other day. In making 

 this transfer the cage containing the nymphs was carried to a separate table, 

 used only for this purpose. The clean cage, labelled and containing fresh 

 lettuce leaves, was placed on the same table, and the nymphs were carefully 

 lifted from each stale leaf of lettuce to the fresh cage by using a very fine 

 camel's hair brush. The nymphs were carefully counted while moving them 

 from one cape to another, and it very rarely happened that a nymph was 

 accidentally thrown away with the discarded lettuce. 



To keep the proper degree of moisture in the cages proved to be a very 

 troublesome problem. A certain amount of moisture is necessary to preserve 

 the food, but if the cotton which is wrapped around the stems of the 

 wheat &c., is too wet, some of the water may droj) on to the glass bottom of 

 the caoe, and if a bug falls on its back in even a few drops of water, it 

 frequently cannot regain its normal position, and may die in a few hours. 

 This dano-er must be controlled, for bugs frequently drop from the top or 

 sides of the cage, and from the food. Too much moisture is even more 

 dangerous for the larval stages. The drops that collect on the inner surface 

 of the class cover of the wet chamber dishes and fall to the bottom of the 

 dish, mean death to any nymphs that may fall on their backs into even one 

 drop of moisture. It requires constant vigilance to avoid this danger, by 

 frequently wiping off the moisture that collects on the inside of the glass 

 cover. We tried to avoid this risk by placing ordinary filter-paper on the 

 bottom of the cages, but this did not work well, for the tarsi of the bugs 

 frequently caught in the fibres of this coarse paper. But by substituting the 

 Grerman hardened filter-paper for the coarser paper, we got rid of this 

 difficulty. The filter-paper must be cut to fit the bottom of the cages exactly, 

 and it must be kept moist, but not too wet, for too much moisture will rot the 

 delicate lettuce leaves. We have frequently watched the adult bugs, and 



