330 ENTOMOLOGICAL NEWS. [J u ty> ' I2 



collect some of these globules and give them to the parasites as a 

 substitute for their accustomed host eggs. The idea seemed so 

 absurd, however, that only after a complete failure to obtain moth 

 eggs was it put into execution. 



Twenty of the juice globules were collected, some of them a little 

 smaller, some a little larger than the eggs of the bollworm, Heliothis 

 obsoleta, a favorite host of Trichogramma. These were placed in a 

 small glass vial, and a female Trichogramma which had been in a tube 

 with males of the same species was introduced. She quickly went to 

 a globule and soon oviposited three times in it. There was a short 

 interval between each two ovipositions. She then oviposited in each 

 of four other globules. Then after running about for a few seconds 

 she rested on the side of the vial. The vial being shaken slightly, she 

 ran about again, got on a globule, but did not oviposit. In a few sec- 

 onds she became motionless. The tube was slightly moved, and the 

 parasite ran about but did not oviposit. She soon came to a resting 

 position on the side of the vial, and was not observed to oviposit 

 again. 



The globules were observed carefully for several days, and, as may 

 be expected, they all dried up without the emergence of any parasites. 

 The female of Trichogramma is usually represented as carefully 

 inspecting the host egg to learn if it is suitable for oviposition, and I 

 have often observed females walking over the eggs and touching them 

 many times with the antennae, but it seems from these observations 

 that the female is unable to ascertain whether the egg is suitable or 

 not. 



Unless it be admitted that the mature female is impelled to oviposit 

 in anything like a moth egg which is at hand, it seems clear that she 

 is unable to learn not only whether or not a host egg is already para- 

 sitized, unless it has turned black, but even whether it is of a suitable 

 species or whether it is an egg at all. The parasite under considera- 

 tion is known to have some forty-three hosts, and is supposed to 

 oviposit in any soft-shelled egg, within certain limits as to species. 

 The globules of okra juice were surrounded by a film formed by the 

 exposure of the juice to the air, and were fairly good as an imita- 

 tion of the egg of a Noctuid. It seems probable that Tiichograinma 

 oviposits in many unsuitable eggs, at least undler conditions of 

 scarcity of its usual hosts. 



The reason for the careful examination of the egg by the female 

 is a subject for further speculation. Possibly the examination serves 

 merely to locate a suitable place for the insertion of the ovipositor. 

 T. E. HOLLOWAY, U. S. Bureau of Entomology, Audubon .Park, New 

 Orleans, La. 



