52 THE GEAPE BOOT- WORM. 



LIFE HISTORY OF FIDIOBIA FLAVIPES ASHM. 



During the summer of 1909 the junior author had opportunity to 

 rear Fidiohia Jlavipes Ashm. (fig. 24) and to make some observations 

 relative to its habits and occurrence in the Lake Erie grape belt. 



The parasitized root-worm eggs can be readily recognized in that 

 they assume a brownish-yellow cast and become gradually darker 

 with the development of the parasite. The grape root-worm eggs 

 when first deposited are whitish, but soon take on a yellowish cast. 

 In view of the semi transparent eggshell it is possible to observe the 

 development of the different stages. 



Parasitized eggs were obtained in the vineyards July 13, from 

 which adults issued on August 3. These adults were then placed in a 

 vial August 4, with fresh eggs which had been laid in breeding cages 



the previous day. On August 7 an 

 irregular area could be distinguished 

 in the center of each egg, indicating 

 a breaking up of the yolk tissue. 

 On August 11 the parasitized eggs 

 were already of a dark yellowish- 

 brown cast. In one extremity of 

 the egg there began to appear an 



Fig. 24,.— Fidiohia jlavipes, an egg-parasite of , j 1.1 i i j 



the grape root-worm: Adult and enlarged empty SpaCC and the larva COuld 

 antenna. Very greatly enlarged. (Orig- be distinguished feeding toward the 



Opposite end. On August 14 most 

 of the parasite larvie pupated. Two or three days after pupation 

 the eyes could be distinguished in the form of black spots, and a few 

 days previous to the time of the emergence of the adults the entire 

 pupa assumed a dark color. The minute hymenopterous flies emerged 

 August 28, 29, and 30. 



In summarizing these data, we get 10 days for the egg and larval 

 stages, 14 to 15 days for the pupal stage, or a total of 24 to 26 days 

 for the whole life cycle. It is possible to recognize parasitized eggs 

 3 or 4 days after they become infested. Adult insects lived from 5 

 to 7 days in a test tube without food. 



To determine the development of parasites from root-worm eggs of 

 different ages and also to test in a general way the resistance of egg^s 

 of different ages to parasitism, the following experiments were carried 

 out as summed up in Tables XXI and XXII: 



