TWELFTH ANNUAL REPORT g5 



during the year, with the hope of crossing them with our stock. 

 Unfortunately, most of the Japanese eggs died, probably due 

 to abrupt climatic change. Sooner or later, we shall be obliged 

 to obtain some fresh stock of silkworms of a polyvoltine race 

 from India, for recrossing with our stock. The desirability of 

 a thoroughly competent person to give his entire time to silk 

 culture and its propaganda in the Philippines becomes more 

 apparent each year. 



Field work. — In November the sugar-cane leaf hoppers in Los 

 Bahos, Laguna, were investigated. A species of the genus 

 Perkinsiella had been very abundant in small patches of sugar 

 cane adjacent to the properties of the Calamba Sugar Estate Co., 

 but it was found that a small Qgg parasite belonging to the genus 

 Paranagrus was apparently holding the pest in check. This 

 parasite is similar to a species which has been introduced arti- 

 ficially into Hawaii, and appears to be performing naturally the 

 functions which those who work on sugar-cane insects in Hawaii 

 have been obliged to obtain at much labor and expense. 



From April 5 to June 7, 1913, Mr. Schultze was detailed on 

 a biological expedition to Palawan, where a large number of 

 new insects were found. 



In April, Mr. Banks was detailed to Aparri, Cagayan, to take 

 charge of the eradication of flies in that place, and subsequently 

 to investigate the cacao pests reported from Ilocos Norte. 



At Aparri, it was found that flies, similar in appearance and 

 habits to the common house fly, were breeding under the most 

 unexpected conditions; namely, in the large jars of macerated 

 salt fish, known in that region as hogong, and extensively ex- 

 ported to various points in Ilocos Norte and Ilocos Sur. Public 

 mass meetings for the enlightenment of the people on this subject 

 were held, and the municipal authorities passed an ordinance 

 compelling the manufacturers of this substance so to close their 

 jars that it would be impossible for flies to have access to the 

 contained material for the purpose of laying their eggs or, in 

 case they had laid them previously, to prevent the escape of 

 those flies or maggots which might develop therein. There has 

 been a decided decrease in the number of flies in the town. 



In Ilocos Norte numerous species of insects, hitherto not re- 

 corded as coming from cacao, were found on a large plantation 

 established about twenty years ago and practically abandoned 

 until within the past year. Collections of both the insects and 

 the damaged plants were made, and certain material was brought 

 to Manila for further study. 



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