416 - JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



their attached suckers by pruning and burning with the gasoline 

 blast torch, as described in Bulletin 56 of the Arizona Agricultural 

 Experiment Station. A year after such treatment, if the tree appears 

 to have been successfully treated, as has proved the case with 90 per 

 cent of those burned in Arizona, the suckers may be cut and trans- 

 planted, still infested, however, with Marlatt scale. 



When the old tree has ceased bearing suckers it becomes practicable 

 to clean the bole and burn it more thoroughly to eradicate Marlatt 

 scale, the tree or orchard of trees being thus finally freed from both 

 infestations. Transplanted suckers, which at the time of cutting 

 could not have borne the severe burning necessary to deprive them of 

 Marlatt scale, can be followed up in the same way and finally freed 

 of infestation. 



SOME RECENT MANUALS OF PARASITOLOGY 



By Wm. a. Riley 



As a rule the economic entomologist is expected to pass upon all 

 questions of parasitology, whether they relate to insects or other 

 forms. The recently awakened interest in medical entomology has 

 made it more imperative than ever that the student planning to go 

 into work in economic entomology should have a good basis in general 

 parasitology. In this connection, the question as to reliable, up-to- 

 date reference-books and compendia is one that frequently arises, 

 and it has seemed that a brief discussion of some of the available 

 texts, with special reference to the latest, would be of help. 



Few of the branches of biological science have made more rapid 

 progress during the past few years than has parasitology, and books 

 which were standard until recently, are no longer satisfactory refer- 

 ence books for even those who are not primarily interested in this field. 

 This is especially true of the very phases of the subject which are most 

 intimately connected with the entomological work. 



Leuckart's great classic, "Die menschlichen Parasiten," will never 

 lose its value as a discussion of the biological principles underlying 

 parasitism, but it was written j'ears before the pioneer work on the 

 relations between arthropods and parasitic protozoa were suspected 

 and even the discussion of the vermiform parasites is superseded. 

 Moreover, it is long since out of print and the English translation, by 

 Hoyle, is now seldom offered. The work is of such fundamental value 

 that any opportunity to obtain a copy should be seized. 



Of the works on this subject of a more economic bearing, none has 

 been more widely cited and quoted in this country than has Railliet's 



