PREVIOUS WORK WITH INSECT PARASITES. 33 



secured leave of absence and started for America, carrying with him 

 a box of parasitized scales, and landed at New York on June 2. 

 His box of parasites was at once forwarded to Washington, and the 

 Bureau of Entomology notified Mr. Ehrhorn by telegram, repacked 

 the box, and sent it to California. Mr. Ehrhorn succeeded in tem- 

 porarily establishing the Scutellista indoors and out around his home 

 at Mountain View, Cal. September 19, 1900, Mr. C. W. Mally, 

 Lounsbury's assistant, sent two more boxes by post direct to Cali- 

 fornia, addressing them to S. F. Leib, of San Jose, notifying the 

 senior author to wire Mr. Ehrhorn to be on the lookout for them. A 

 third lot was sent October 31 of the same year. These later sendings 

 were small, and both failed to yield living parasites. More were 

 requested, and on Lounsbury's return to South Africa a box was 

 shipped in cool chamber to England and thence direct to California 

 by express, Lounsbury's letter of February 28, 1901, to the bureau 

 stating: "To avoid extra delay in transmission the box goes direct 

 to California, but will you kindly have a message sent to Craw to 

 advise him of its coming ?-" Unfortunately the box was detained by 

 a customs officer at New York, but the bureau secured its release by 

 the Government dispatch agent, Mr. I. P. Roosa. A few parasites 

 emerged after arrival, but failed to propagate. October 1, 1901, 

 Lounsbury started another sending by letter post to insure quick 

 transit and noninterference by customs. These boxes were delivered 

 to Mr. Craw on October 31. Only four females of the Scutellista 

 were reared by Mr. Craw, and probably to these four females are due 

 all of the Scutellistas subsequently occurring in California. This is 

 the full story of the introduction of the species, taken from the letter 

 files of the Bureau of Entomology and the letter files of Mr. Louns- 

 bury in Cape Town. 



Mr. Craw was remarkably successful in his rearings, and during the 

 following three years constantly distributed colonies in different por- 

 tions of California. By July, 1902, he had distributed 25 colonies. 

 It was in the southern part of the State that the parasite did its best 

 work, and there for a time it surpassed the most sanguine expecta- 

 tions of everyone. It was established in every county south of Point 

 Conception and had become very plentiful in Los Angeles, Orange, 

 and San Diego Counties. In the colonization districts by midsum- 

 mer, 1903, it was estimated that over 90 per cent of the black scale 

 had been destroyed. A year or so later there was great mortality 

 among these parasites caused by a sudden increase in numbers of 

 a predatory mite, Pediculoides ventricosus Newp. (fig. 7), which 

 destroyed the larvae in vast numbers. The Scutellista gradually 

 recovered from this attack, and is at present to be found in very 

 many localities in California, keeping the black scale partly in check. 



62188°— Bull. 91—12 3 



