OF WASHINGTON, VOLUME XV, 1913. 93 



mens of all 4 species were reared from the same egg-mass. The 

 writer has placed a summary of the number of each species reared 

 from 19 egg-masses in table III. 



The totals for this table, omitting the partial records in Nos. 

 7, 9, 13, and 16, show that out of 7187 -eggs, 2438, or 33.9 per cent, 

 hatched as larvse; 2073, or 28.8+ per cent, remained unhatched; 

 and 2676, or 37.2 per cent, gave out parasites. Of these parasites 

 Telenomus sphingis emerged to the number of 1515, or 65.6+ per 

 cent; Trichogramma minutum emerged to the number of 49, or 

 2.1+ per cent; Ooencyrtus sp. emerged to the number of 686, or 

 29.7+ per cent; and Baryscapus sp. emerged to the number of 59, 

 or 2.1+ per cent. The percentage of parasitism should run con- 

 siderably higher than this, as many of the unhatched eggs were 

 found to contain dead parasites. 



It was observed in the experiments with these egg-parasites that 

 Trichogramma minutum would emerge from the eggs at the same 

 time that the larvae of the host were hatching, indicating a short 

 period of development for this species. 



Telenomus sphingis and Ooencyrtus sp. were observed to emerge 

 from the host eggs about five days after the larvae had emerged, 

 and frequently both species would emerge from an egg-mass at the 

 same time. 



The fourth species, Baryscapus sp., was observed to emerge from 

 three to eleven days after T. sphingis and Ooencyrtus sp. had 

 emerged. 



Many of the egg-masses collected were almost totally parasitized, 

 as from nearly every egg a parasite emerged. In others it was 

 observed that although the eggs were extensively parasitized, many 

 of the parasites either died in the eggs without cutting a hole or 

 after cutting an emergence hole could not free themselves and died 

 while partially out of the host egg. In one case observed, from a 

 mass of 968 eggs only 176 parasites emerged, while 694, after par- 

 tially eating their way out, died in the shells. This was probably 

 owing to a lack of moisture, due to the artificial method of rearing 

 in vials. 



Telenomus sphingis was by far the most abundant and important 

 egg-parasite of Datana integerrima of the four species under obser- 

 vation. This is a minute, black-bodied insect with yellowish legs 

 and hyaline wings. The process of oviposition of this species was 

 observed and will illustrate in a general way the process for the 

 others. 



The female crawls rapidly over the eggs with the antennae in con- 

 stant motion, examining them until she finds one that seems suitable. 

 She then halts and explores the surface of this egg with her antennae, 

 at the same time turning around repeatedly until the entire surface 

 of the egg beneath her has been examined. If satisfied, she takes a 



