316 



Phylum Arthropoda 



the top of the lamp chimney is placed a covering of cheesecloth. For 

 the tiny ist instars it was even necessary to double the cloth to keep 

 the nymphs from straying away from the plant. It is necessary to use 

 lamp chimneys for the first instar or two because they are so small at 

 this time and so restless that they become lost easily in any larger 

 space. For later stages wire cages would be better because the plants 

 would do better in less cramped quarters and no difficulty is likely to be 

 experienced in keeping the larger nymphs under observation. 



ARTIFICIAL FEEDING OF LEAFHOPPERS* 



A METHOD has been devised whereby a reasonably large number of 

 leafhoppers may be caged and fed simultaneously upon a nutrient 

 solution. It consists (Fig. 65) of a shallow "saucer" to which had been 



sealed a vertical L tube. This 

 vessel is capped with a mesentery 

 membrane of the type recom- 

 mended by Carter.** The solution 

 is added to the feeding apparatus 

 until the liquid is in contact with 

 the entire surface of the membrane 

 by means of the side arm, which is 

 corked to prevent contamination. 

 This feeding vessel may be washed 

 and sterilized in alcohol without 

 removing the membrane or impair- 

 ing its efficiency. 



For use with this feeding dish, 

 a cage made of a 3-inch cylinder of 

 1 % -inch glass tubing, capped at 

 both ends with a fine open-mesh cloth such as georgette or scrim, is 

 employed. The upper end of the cloth capping has a small opening for 

 admission of the test insects, which is at other times closed by a cotton 

 plug. The cage containing the test insects is placed upright upon the 

 membrane surface over the solution. 



"With this arrangement, feeding will begin almost at once and freely 

 continue as long as the insect lives. No evidence of unwillingness or in- 

 ability of the leafhopper to locate the solution or to feed upon it was 

 found. Furthermore with this arrangement it was possible to transfer 

 feeding insects from one solution to another without handling them, 



♦Abstracted from an article in Science 79:346, 1934, by R. A. Fulton and J. C. 

 Chamberlin, U. S. Bureau of Entomology and Plant Quarantine. 



** Animal mesentery sold under the name of "fish skin" at a drug store. /. Agric 

 Res. 34:449, 1927, and Phytopathology 18:246, 192S. 



Fig. 65. — -Apparatus devised for simul- 

 taneously feeding large numbers of homop- 

 terous insects on a nutrient solution. 



