344 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



ber may be glued to each tube so that a record may be kept of the 

 work. 



For shipment, the tubes containing parasitized eggs may be packed 

 in pasteboard mailing cases. In the work with which the writer was 

 connected, a little cotton batting was placed in each tube to prevent 

 the eggs from shaking, but Mr. S. Leefmans, who received the eggs in 

 Holland, suggested that pieces of very thin paper be used instead of 

 cotton, as the parasites on emerging were liable to become entangled 

 in the cotton. The writer does not know whether the thin paper was 

 more satisfactory than the cotton. Each tube should be packed in 

 cotton in a tube that is somewhat larger, and the larger tubes should 

 be packed in cotton in the case. If cold storage is used — and it is 

 desirable for long shipments, such as across the Atlantic — care should 

 be taken not to remove the insects from the cold storage room at des- 

 tination and to subject them suddenly to a much higher temperature. 

 The mailing cases should be transferred from the cold storage room to 

 thermos jars, in which they may be carried to the laboratory. They 

 should be left in the thermos jars for about twenty-four hours, in which 

 time they will gradually have come to the temperature of the labora- 

 tory. The temperature of the cold storage rooms on the ships used 

 by the writer was said to be 38° F. The freshly parasitized eggs, 

 packed as above, were sent by ordinary mail from Brownsville, Tex., 

 to New York, where they were supposed to be placed in cold storage 

 immediately by the steamship company. The several days during 

 which they were on the road between Brownsville and New York gave 

 the eggs time to turn black before being placed in cold storage. 



Perhaps the most important point to be realized by an entomologist 

 who undertakes to rear Trichogramma and other egg parasites is that 

 such minute insects require special treatment because of their small 

 size. The cages designed for them, the methods of feeding, shipping, 

 etc., must all be considered with due regard to this factor. 



Several entomologists of the writer's acquaintance are now engaged 

 in work in connection with the control of certain injurious insects by 

 the introduction or the artificial propagation of small hymenopterous 

 parasites, and it is hoped that these and other workers may find some 

 helpful suggestions in this article. 



