April, 1918] Parasites of LeaJ-IIop per s 197 



In some species there is just enough food present in the hopper 

 to feed but one dryinid, while others may be seen bearing from 

 two to as many as eight parasites. In fact, with Brucomorpha 

 ocidatiis, two or three parasites are more often found attached 

 than one, and these may all mature if the host is a large, robust 

 individual. Generally the parasites on a hopper are of one 

 species, but may be of two different species. One sex seems 

 as readily attacked as the other. Some species confine their 

 attacks entirely to nymphs, others to adults, and others to 

 both nearly mature nymphs and adults. Once a nymph is 

 parasitized it never becomes adult, in so far as observed by the 

 writer. Keilin and Thompson (1915) state that the Typhlo- 

 cybidce parasitized by Aphelopiis malaleuciis Dalm. are ovi- 

 posited in before becoming adult. With Erythroueura tricincta, 

 parasitized also by a species of Aphelopiis, adults have been 

 kept in captivity as long as a week before a sac appeared 

 externally. It would seem, then, that with this species the 

 egg is laid after the host becomes winged. Nymphs parasitized 

 by Gonatopiis and its allies never become adults, no matter 

 if they are in their last instar. Gonatopiis erythrodes (Perk.) 

 attacks nymphs in the second, third and fourth instars, but 

 prefers nymphs of the fourth instar. The place selected for 

 oviposition with a given species of dryinid is generally restricted 

 not only to either the abdomen or thorax, but also to certain 

 segments of these, or in certain positions on these segments, as, 

 for instance, with Haplogoiiatopiis americanus Perk. Its sacs 

 are found invariably protruding dorsally between the last two 

 or three abdominal segments. Very often a species of dryinid 

 confines its attacks to one species of hopper. Others may 

 parasitize closely-related species; and still others may parasitize 

 species in different genera. 



After oviposition the dryinid drops the hopper and runs 

 away. The latter recovers rapidly, and generally within five 

 minutes recovery is complete and feeding is resumed. The 

 number of eggs a female may lay is probably considerable, 

 though not as large as with many hymenopterous parasites. 

 In captivity the largest number of eggs obtained was thirteen, 

 and the greatest number in a single day was six. These figures 

 are unquestionably much too low for normal conditions. The 

 females are ready for oviposition as soon as they have fed after 

 emergence, so that the oviposition period must extend through- 



