530 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



cover. When they had deposited a number of eggs on the plants, 

 several of the parasites were introduced; they immediately began 

 ovipositing into the eggs of the Meromyza, readily verifjqng the ob- 

 servation of 1908. The interesting method of oviposition was wit- 

 nessed at this time by Messrs. Packard, Larrimer, and Wade, who 

 were working with the writer at the Wellington (Kan.) laboratory. 

 These men, together with the writer, watched the development of the 

 host and the parasite. It required only a few days for the Meromyza 

 eggs to hatch. The host larvae matured and reached the pupal stage 

 in about ten weeks, and in about twelve weeks the adults of both host 

 and parasite matured. Further observation in the field and laboratory 

 indicated that the adults of the host and parasite matured about the 

 same time. This, of course, would be necessary in the life economy of 

 the parasite. 



In comparing the size of the host and parasite, it was found by Mr. 

 Larrimer that the egg of Meromyza americana averages about 1.12 

 mm. in length, and .28 mm. in diameter, while the Coelinidea egg 

 measures on an average about .18 mm. in length and .04 mm. in 

 diameter; the Meromyza. americana egg being seven times larger than 

 the Coelinidea egg. The Coelinidea eggs were dissected from the eggs 

 of the Meromyza. The egg is watery white, oblong, with oval ends, 

 very similar in shape to the Meromyza egg. 



The adult parasites were introduced into the cage containing the 

 Meromyza eggs, on the 10th of February, and they began ovipositing 

 into the eggs at once, apparently not missing an egg. The IVIeromyza 

 eggs began to hatch on the 12th of February, continuing to hatch for the 

 next few days. The larvae did not develop very rapidly, and were yet 

 quite small on the 10th of March. On this date a number of them 

 were measured, the average being about 2.66 mm. in length and .36 

 mm. in diameter. These larvae were then dissected and Coelinidea 

 larvae removed from them, which larvae measured on an average .64 

 mm. in length and .19 mm. in diameter. The Calinidea larvae were 

 in the fatty tissues of the Meromyza, and apparently were not disturb- 

 ing the alimentary tract, thus not interfering with the development of 

 the Meromyza larva. 



Dissecting the Meromyza larva in search of the Coelinidea larva 

 was rather disastrous to the latter. However, a few were successfully 

 dissected, and it was assumed from the data thus obtained that the 

 Coelinidea egg hatches very shortly after the egg of the Meromyza, and 

 the two larvae develop along together, the Coelinidea larva not maturing 

 until after the Meromyza pupates. 



According to further observations in the laboratory by Messrs. 



