Dipterous parasite, from which no mature insect was bred, but 

 it unquestionably belonged to a species of Pipunculus. 



The immediate and actual results of Mr. Koebele's consign- 

 ments of North American insects were on the whole disap- 

 pointing. Neither from a purely scientific point of view, how- 

 ever, nor from a practical standpoint, was this material done 

 justice to. I wish to lay particular stress on this point, because 

 it shows at once the frequent value of work of a highly technical 

 nature for practical purposes, even though it may be largely 

 incomprehensible to any save an entomologist, and even to any 

 save an advanced student of entomology. When Mr. Koebele's 

 living specimens came to hand, I was fairly well acquainted with 

 -the published facts already known about these leaf-hopper para- 

 sites. TJiis j)ublished information, however, was of the most 

 meagre description, apparently only three or four of the great 

 numbers of known species having been bred or having had their 

 habits studied. Further, of those which had been bred, in most 

 cases only a few individuals had been reared and information as 

 to diversity or uniformity of habits was almost wanting. In 

 one case only, one of these parasites had been recorded as at- 

 tacking two species of leaf-hopper, and those so utterly differ- 

 ent in all points of structure, as to lead one to suppose that the 

 Dryinidae might be indiscriminate in their choice of host. I 

 refer to the case of Laheo typJilocybac and Dryvius oniiciiidis dis- 

 cussed in this Bulletin on pp. 485 and 492. We now know that, 

 in reality, these parasites generally are most particular as to 

 their choice of host, and those which attack leaf-hoppers of the 

 Delphacid group, to which our cane-hopper belongs, do not 

 even extend their attacks to species outside this group, still less 

 will they attack such different hoppers as are included in the 

 great Jassid series. Now the living material sent to me by Koe- 

 bele from North America included parasites of many small leaf- 

 hoppers, belonging to most diverse groups, many of which 

 would never have attacked our cane-hopper, as their structure 

 plainly shows. It was not until I was in Australia and had 

 leisure to examine Australian parasites with some care that I 

 discovered the microscopic characters, which are always found 

 in those species which attack leaf-hoppers of the Delphacid 

 group, as opposed to those preying on Jassids. For want of 

 this knowledge. Mr. Koebele's material from North America 

 was, as T have said, not done full justice to from a practical 

 point of view ; much time being wasted on parasites that never 

 would have attacked our cane leaf-hopper. Still at least two 



