1914.] PUBLIC DOCUMENT — No. 31. 39 a 



lected breeding flock of 144 birds to produce: (a) eggs, (6) 

 fertile eggs, (c) batchable eggs, (c?) viable chicks, (e) vigorous 

 adults ; and of the ability of each hen to transmit these qualities 

 to her progeny. 



In the department of pomology a bulletin, — "A Study of 

 Variation in Apples," — found later in this report, has been 

 issued. This bulletin presents the conclusions based on a study 

 of climatic and other conditions upon the size, shape and other 

 characteristics of apples. The investigation shows in general 

 that a high temperature is favorable to the development of rela- 

 tively flattened forms, and that, on the other hand, a low tem- 

 perature, especially during a period immediately following the 

 setting of the fruit, is favorable to elongated forms. 



In the veterinary department methods of diagnosing infec- 

 tion with the bacterium which causes white diarrhoea in the 

 chicks of the domestic fowl have been studied, and a bulletin 

 on the subject — "On the Diagnosis of Infection with Bacte- 

 rium Pullorum in the Domestic Fowl " — is found later in 

 this report. The conclusion is that the examination of the eggs 

 from suspected hens is not a practicable method for rapid diag- 

 nosis. On the other hand, macroscopic agglutination tests of 

 the blood can be rapidly made and appear to give reliable in- 

 dications. 



In the entomological department the life history of the mar- 

 guerite leaf miner {Phytomyza chrysanthemi Kow.) has been 

 worked out and methods for its control discovered. Numerous 

 insecticides have been tested. A very active and efficient para- 

 site of the San Jose scale has been discovered. The work of 

 this parasite has been found very effective, having resulted in 

 the destruction of over 90 per cent, of the scales on the branches 

 of trees examined in many cases. The entomologist has sup- 

 plied parasitized scale to stations in a number of other States 

 and is still supplying material on request. A fuller report con- 

 cerning this scale and other work of the entomological depart- 

 ment will be found in later pages. 



The report of the treasurer immediately follows the director's 

 report. 



WM. P. BROOKS, 



Director. 



