95 



the plant, and the eggs adhere so firmly together, and to the place of 

 deposit, that they are not so easily seen and are also with extreme dif- 

 ficulty detached. The eggs observed required about a month to hatch. 



The newly hatched larva, which is pale yellowish in color with light 

 brown mouth-parts, is quite active, and upon hatching burrows imme- 

 diately into the ground, where it soon acquires a bluish hue. 



The larval period does not appear to have been ascertained, but it is 

 with little doubt at least one month, and perhaps two or three more, 

 this stage being passed entirely in the ground, where the pupa state is 

 also assumed. As this species lives by preference, at least in most of 

 the United States, under glass, there can be no great regularity in the 

 duration of the periods of transformation. The insect may, in fact, 

 be found in all stages during the winter and early spring months, 

 injuiy appearing to be most noticeable in December. 



NATURAL ENEMIES. 



A single carnivorous insect appears to have been recorded as prey- 

 ing upon the larvae of this beetle, this observation having been made 

 in the rearing cages at this Department in 1878. The insect was a 

 wire worm, the larva of a click-beetle, and was somewhat doubtfully 

 referred to Drasterius amabilis Lee. 



Toads are frequently found in greenhouses, and sometimes are pur- 

 posely put in such places to prey upon destructive insects. They are 

 known to feed upon insects related to this rose beetle, and probably 

 feed upon the species in question. 



Natural enemies that have been observed by Mr. Koebele in Hawaii 

 include the mina bird and mongoose. 



METHODS OF CONTROL. 



The beetles are so long-lived and hardy that it is difficult, if not 

 impossible, to destroy them by the use of ordinary insecticides, even 

 hydrocyanic-acid gas being practically powerless against them used at 

 a strength that would not kill the plants affected. The remedy which 

 has found most favor is to search for and destroy the beetles, and a 

 good time for this work is during the months of November and Decem- 

 ber, when the beetles may often be found congregated upon the plants. 

 By persistently following this method the insect has been practically 

 exterminated in many greenhouses which it formerly infested. By 

 killing the beetles the number of larvae will of course be lessened. 

 Plants showing severe injury should be pulled out and the soil about 

 them searched for the .larvae; or the larvae may be killed b}^ means of 

 the bisulphide of carbon applied to the soil about the roots of the 

 affected plants. It should be inserted by means of a metal syringe, a 

 few drops here and there about the roots being sufficient to destroy the 



