342 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



"Therefore a very large quantity of host eggs is a principal question. 

 Mr. Fiske had infested eggs in cold storage (28-30° F.) for about ten 

 months, after which time the adults emerged normally. It is neces- 

 sary to put the infested eggs in the cold temperature at the moment 

 when they are beginning to turn black." 



The easiest and almost the only way of collecting very small egg 

 parasites is to collect eggs parasitized by them, and to rear the parasites 

 from the eggs. The collected eggs should be separated as well as 

 possible from the leaves or corn silk (in the case of Heliothis eggs) on 

 which they were deposited. They should then be put in glass tubes 

 about 8 mm. wide by 24 mm. in length, about ten or fifteen eggs to a 

 tube. A piece of fine cotton batting is very good for use as a stopper. 

 The eggs which are not parasitized will usually hatch before the para- 

 sites emerge from the other eggs. The larvae from the unparasitized 

 eggs should be removed from the tube. 



The parasites may be expected to emerge within a short time after 

 the eggs turn black. Sometimes several adults of Trichogramma 

 emerge from one egg, so that quite a number of parasites may be 

 found in the tube. A very weak solution of granulated sugar and 

 water should be made and this should be given to the parasites. A 

 good way to feed these minute insects is to moisten the pointed end 

 of an insect pin with the sugar solution, and to insert it into the tube, 

 around the cotton stopper but without removing the stopper. Some 

 of the sugar solution should be made to adhere to the side of the tube, 

 and then the end of the pin should be withdrawn. Only a small 

 amount of the sweet solution is necessary for the parasites. The 

 amount should be so little, in fact, that it cannot be observed very well 

 except with the aid of a pocket lens. If much liquid is given to the 

 parasites they will usually be caught in it and will be unable to free 

 themselves. Naturally, the liquid should not be so thick as to be 

 sticky, A sugar solution which is merely sweetened water is best. 



Copulation will occur soon after both males and females have emerged 

 from the eggs in the tube. The experience of the writer indicates, 

 however, that it is best to leave the females with the males for about 

 twenty-four hours before giving them host eggs for oviposition. If a 

 female is given host eggs within a few hours after emergence it seems 

 that there is some possibility that she may escape fertilization. 



When it is desired to have the parasites oviposit, they may be intro- 

 duced into a tube (size 8 mm. by 24 mm.) in which a number of fresh 

 host eggs, or host eggs which have been kept in cold storage, and a 

 minute particle of the sugar solution have been placed. (The writer 

 did not use the very small tubes recommended by Mr. Fiske because 

 he could not obtain them readily.) The manner of transferring the 



