﻿deposited, it is not for some time that the characteristic larval 

 sac becomes evident externally. In the case of Eclitlirodclpkax, 

 I could distinguish the larval sac, having the appearance of a 

 minute transparent vesicle, at the end of four days with the 

 naked eye In the case of a California species of Haplogonoito- 

 pus, the period was not less than a week. On one occasion 

 three cane leaf-hoppers were placed in a large glass jar with the 

 Haplogonatopiis, and two of them were seen to be quickly 

 seized and stung. The next day the parasite was removed to 

 another cage. At the end of six days, when the hoppers were 

 examined, no sign of the larval parasite was noted, even with the 

 aid of a weak lens, and it was supposed that they were unafifect- 

 ed. However on the ninth day, when they were again examin- 

 ed, the parasitic larvae were of considerable size, and obvious to 

 the naked eye. The third hopper of the above produced no 

 parasite and probably was not stung. As soon as the larval sac 

 becomies visible, it is usually but a short time, a few days or a 

 week before the larva becomes mature. The length of time no 

 doubt varies somewhat according to the species, and according 

 to climatic conditions. 



The larva of the EchtJirodclphax fairchildii while still attached 

 to the hopper, appears as a small, nearly circular, impressed, black 

 object, adherent to the young leaf-hopper. The latter seems 

 h.ardly to be inconvenienced by the parasite, remaining as active 

 and plump as the non-parasitized individuals. It is always the 

 immature hopper that is attacked and a single hopper may sus- 

 tain one or two parasites. They are generally fixed beneath the 

 lobes, which develop into the tegmina or upper wings, one on 

 each side of the body, if two be present; they are, however, 

 sometimes found beneath the true wings. 



After a time, however, (always shortly before the full growth 

 of the parasitic larva) the hopper becomes sluggish and then en- 

 tirely stationary. This may happen either shortly before or 

 not till some time after the black shell-like covering or larval 

 sac of the parasite splits by a longitudinal (mediodorsal) fissure 

 and exposes the back of the white maggot within. This tor- 

 pidity of the leaf-hopper and the splitting of the covering of the 

 parasite is the outward sign of a change of habits in the latter 

 (being coincident with a moult and change of form of the para- 

 site). From this time until t'he hopper dies and the magg'ot 

 finally quits hold of its prey the sight as examined under a lens 

 forms one of the most repulsive sights that natural history can 

 afford. 



