ing in water or water covered with a layer of kerosene oil. Sim- 

 ilar houses are in use at our Experimental Station (see fig. of 

 exterior, page viii, and on page ix one corner of interior with 

 cages). It is necessary to take care that grass and weeds do not 

 grow up so as to form a connection with the house ; and, as will 

 be noticed in the figure, the steps are built separately, and do not 

 actually touch the house. The sides of these houses are covered 

 with copper wire and in stormy weather blinds of thick white 

 canvas can be let down for shelter from the rain, or on other days 

 as a screen from excessive sun. The wire-mesh is fine enough 

 to prevent the escape of a moderate-sized lady-bird. The earth 

 used for plants in these houses is soaked in l^oiling water to 

 kill ants and other injurious insects that may be present in any 

 stage, and the wooden tubs, in which the plants are grown, arc 

 similarly treated. These tubs of Japanese make (manufactured 

 as containers of the Japanese drink "saki") often afiford hiding 

 places to centipedes, cockroaches, ants and other most undesir- 

 able insects. On one occasion some years ago, in one night T 

 lost a whole brood of about sixt>- 

 individuals of a beneficial insect, "^ '"'^"' 



that I wished to establish, from 

 the attack of a small centipede 

 accidentally carried into a house 

 in a saki-tub, that 'had not been 

 treated with boiling water. These 

 saki tubs, as shown in the adjoin- 

 ing figure, are excellent f(H- 

 growing cane or other plants, 

 which can be covered with a cap 

 of fine muslin, fastened on a light 

 bamboo-frame with shellac var- 

 nis'h. Either by a small door or 

 a mere 'hole, which can be closed 

 Avith a plug of cotton, the injuri- 

 ous insects and their parasites 

 can readilv be turned into such a 

 cage and allowed to breed there. 

 In establishing the minute par- 

 asites that destrov the eggs of 

 leafhoppers the following pro- 

 cedure was adopted. I will take 

 the case of Paranagnis optahilis, 

 whose Hfe-historv T have de- 



