200 



The Ohio Journal of Science [Vol. XVIII, No. 6, 



Coincident with the growth of the parasite is the formation 

 and development of the sac. (Figs. 1-7). When the larva 

 hatches it is generally entirely or almost within the body of 

 the host and surrounded by its tissues. As it grows it gradually 

 assumes a curved position, due either to unequal growth or 

 pressure against the host's tissues. It also pushes its way along 

 the path previously made by the ovipositor toward the external 

 point of insertion of the latter. If the egg is laid internally, 

 it undergoes its first m.olt still within the body of the host, as 



Figure 1. 



1-6, side view of abdomen of Deltocephalus inimicus nymphs, showing stages in 

 parasitism by Gonatopiis sp.; 1, egg; 2, second instar; 3, third instar; 4, fourth 

 instar; 5, fifth instar; 6, empty sac; 7, dorsal view of abdominal segments of Delto- 

 cephalus sayi adult 'showing empty sac of Gonatopus sp.; 1st, 2nd. and 3rd. Ex., 

 first, second and third exuviae; Lv., larva; Vp., ventral larval process. 



noted; and instead of entirely breaking through the exuvium 

 dorsally in the normal manner, it splits the latter ventrally and 

 uses it as a buffer in forcing its way outward. It becomes 

 more and more curved in position, and finally breaks through the 

 cuticle of the hopper still with the protection of the first exuvium, 

 which surrounds it as a sort of hood. At no external point, 

 then, is the larva exposed, but with its head and caudal end still 

 in the tissues of the host, it feeds and the first exuvium becomes 

 fused with the cuticula of the hopper by a series of chitinous 

 hooks or other means. At the second molt, the second exuvium 



