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male parasite injures the host more than the female, causing 

 generally a considerable and often large distortion of the body 

 .(2) Both male and female hoppers will copulate though very 

 badly parasitized. (3) Death usually follows after the emer- 

 gence of a male Stylopid, sometimes immediately, sometimes in 

 a few hours, but sometimes not for some days in the case of 

 especially robust hoppers, as also is the case with some wasps. 

 (4) The much more fatal effect of the male parasite is not alto- 

 gether due to the fact that the puparium is much larger (as to 

 its protruded portion) than the mature female, and also usually 

 more chitinized on its hidden segments, but it is largely due to 

 the fact that, when the mature Stylopid emerges, the cap of the 

 puparium being burst open and often altogether removed, a 

 great opening extending far into the interior of the body of the 

 host freely admits both light and air to the viscera, and this 

 clearly produces most injurious and often rapidly fatal results. 

 Possibly too it may be that the male parsite, so far more highly 

 developed than the female, requires for its perfection to draw 

 more heavily for nutriment on its host. Again in the case of 

 leaf-hoppers, at least at certain seasons, no sooner does the 

 male parasite emerge, than a fungous disease at once starts its 

 attack in the opening thus made, the results of which are abso- 

 lutely deadly. Sometimes, but much more rarely, one will find 

 the fungus has developed at the point of protrusion of the female 

 parasite. This fungus disease seems to be a constant con- 

 comitant of Stylopid attack on leaf-hoppers, both in America, 

 Australia and Fiji. I have dealt with this question of the efifect 

 of the parasite at some length, because strenuous ellforts were 

 made to introduce Eleiichiis into these islands (it is to be feared 

 unsuccessfully so far) for economic reasons, and it would be 

 essential in my opinion to bring both the parasites and the con- 

 comitant fungus above mentioned to secure the best results. As, 

 in Fiji, Elcnchns attacks a species of Pcrkinsiclla closely allied 

 to our sugar-cane leaf-hopper, it could probably be much more 

 easily imported from those islands than elsewhere. 



THE GENERA HALICTOPHAGUS AND ELENCHUS. 



The genus Halictophagiis. 



The literature accessible to me that deals with this genus is 

 deficient, and I do not know whether this parasitic insect has 

 been actually bred from the bee genus Halictus or whether its 

 assignment to these common bees is altogether based on con- 



