ENTOMOLOGY. 571 



still somewhat injurious, notwithstanding statements to the contrary. 

 It is often attacked by a fungus as well as by insect enemies, the most 

 active of which are Chilocorus bivulnerus and ApJielinus fuscipennis, 

 which are more useful in the East since they breed throughout the 

 year. The standard California remedy — the lime, salt, and sulphur 

 wash — is thought effective against it. Other injurious insects noted 

 are the white scale (Icerya purchasi), which is now of little importance; 

 the long scale (Mytilaspis </loverii and M. citrieola), introduced about 

 1888-90 from Florida; the rust mite (Phytoptus oleivorus), which has 

 gained a foothold about San Diego and injures chiefly the lemon; the 

 clover mite or red spider (Bryobia pratensis); the peach tree borer 

 (Sannina pacifica), the peach twig borer (Anarsia lineatella), and the 

 grape root louse (Phylloxera vastatrix). 



After the introduction of Vedalia cardinalis, to a subsequent similar 

 experiment is attributed the saving of the citrus industry. The his- 

 tory of the introduction of these beneficial insects is briefly passed 

 over, and of the 5 or G species introduced, Rhizobius centralis, R. debilis, 

 R. tootcoombcp, R. toowoombce lophantce, Oreus chalybeus, and 0. austra- 

 lasicc arc noted as having obtained a foothold and as most important in 

 the vicinity of Santa Barbara. The last-mentioned form has practically 

 disappeared on account of climatic conditions and also of an almost 

 complete disappearance of its food insect, the black scale. Large colo- 

 nics of such introduced insects sometimes fail, to some extent, at least, 

 in consequence of being attacked by small lizards and birds, but in 

 notable instances the ladybird. Rhizobius ventral is, has completely 

 exterminated the black scale and seems to be doing so in other instances. 

 Spraying is shown to be prejudicial to the development of ladybirds, 

 and it is believed by some that spraying where ladybirds are should be 

 prohibited. 



Other important insects thought worthy of note are Gryptolcvmiis 

 montrouzieri, Novius labelei, Gomysfusca, which parasitizes the brown 

 apricot scale, Lecanium armeniacum, to the extent of 75 or 90 per cent, 

 and the twice-stabbed ladybird, Chilocorus bivulnerus, an enemy of 

 the Sa*i .lost' scale, which is thought more important than any of 

 the imported species. 



Continuing, the author discusses the subject of control of insects by 

 the use of washes and by fumigation. The process of "gassing" or 

 "fumigating" differs but little from the method employed some years 

 ago; refined cyanid (98 per cent) is now used in preference to the fused 

 (58 per cent) grade. The latter does not give uniform results. The 

 former may be used in a smaller quantity. Relative to the amount to 

 be used, a table prepared by J. Scott is given, and the statement made 

 that enough of the cyanid should be used to slightly scald the tender 

 terminals of the tree. Forty to forty-five minutes' exposure is thought 

 sufficient. Very compact trees require about one-third more of the gas 

 than others. 



