JOURNAL 



OF 



ECONOMIC ENTOMOLOGY 



OFFICIAL ORGAN AMERICAN ASSOCIATION OF ECONOMIC ENTOMOLOGISTS 



Vol. 6 AUGUST, 1913 No. 4 



SOME METHODS OF HANDLING MINUTE HYMENOPTER- 



OUS PARASITES! 



By T. E. Holloway, Bureau of Entomology, U. S. Department of Agriculture, Audu- 

 bon Park, New Orleans, La. 



A year or so ago the writer had some experience in rearing and 

 shipping the hymenopterous egg parasites, Trichogramma minutum 

 (pretiosa) Riley and Telenomus sp. (probably heliothidis Ashmead). 

 An account of this work has not been published, and the suggestion ^ 

 has been made that the writer prepare a paper on his methods of deal- 

 ing with these small insects. Though Telenomus is more difficult to 

 rear than Trichogramma, the methods given below which were devised 

 for the work with the latter species were found to be suitable for the 

 former also. 



At the beginning of his work the writer had the advantage of some 

 suggestions which Mr. W. F. Fiske made to Dr. L. P. de Bussy, who 

 transmitted them in the following words: 



"He (Mr. Fiske) handles the insects in very narrow tubes (2-3 mm. 

 in width and ^-1 inch long) ; in this way it is very easy to study them 

 with a lens, to see the antennae and to know the sex. 



"Trichogramma breeds parthenogenetically for long generations, 

 if necessary. Mr. Fiske thinks it parasitizes any soft-shelled eggs, 

 but probably only when the larva inside has not yet developed too 

 much. Infertile and dead eggs (after several months of cold storage) 

 will be infested too, and perhaps also ovarial eggs, although this has 

 not been studied. 



"An egg will not give any Trichogramma, when it is very often 

 infested by one or more females. The best way is to give 25 to 50 

 host eggs to one female Trichogramma. Once, as many as 163 Tricho- 

 gramma have been bred from two females. 



1 Published by permission of the Chief of the Bureau of Entomology. 



2 This suggestion was made by Mr. Geo. N. Wolcott, assistant entomologist of the 

 Board of Commissioners of Agriculture in Porto Rico, who has done much work in 

 rearing and shipping Trichogramma and other parasites. 



