13 



— characters, I mean, to correspond with those given by me for 

 the females — I cannot at present state. In some cases I know 

 the mouth parts of the males and females agree entirely in the 

 number of joints of the palpi. At any rate at present the matter 

 is not of much importance, nor will it becomle so until most of 

 the species are bred. In field collecting few males of Gonatopiis 

 (s. 1.) are ever met with. In Mr. Koebele's collection from 

 Arizona there are few or no captured males, though he bred a 

 number of examples of some species. Further in some, and prob- 

 ably in many species, males are very difficult to obtain even by 

 breeding ; perhaps in some this sex does not exist. For economic 

 purposes, we have bred brood after brood of a Vitian Haplogona- 

 iopns and have distributed the females in numbers to many plan- 

 tations to help in controlling the sugar cane leaf-hopper, but in 

 all this time only two or three mlales have ever been bred. In 

 many species, when bred, the males appear to be of such weak 

 and delicate constitution, that one doubts whether, except under 

 particularly favorable circumstances, they can take any part in 

 the propagation of their species. 



In dividing Gonafopus I first separate the species into those 

 which parasitize Jassids and those which attack Fulgorids. This 

 can be done with the greatest ease by examining the chelae of the 

 front less, when one has become familiar with their structure, 

 which I have elsewhere described. Each of these groups is then 

 divided into numerous genera on the number of joints in the palpi, 

 the labial palpi being always formed of two or three joints, the 

 maxillary having from two to six. In my opinion the genera 

 with three-jointed labial palpi are essentially different from those 

 with two joints and this remark applies to both females and males. 

 The use of the number of joints in the palpi for the subdivision 

 of Gouatopus appears to m!e exactly comparable with that in the 

 genus of wasps Syiiagris, but it is more necessary in the former 

 on account of the much greater number of species that exist. The 

 main facts concerning Syiiagris (s. 1.) can be found in the works 

 of de Saussure by those interested. 



Considerable caution is necessary in dealing with the specific 

 value of color, and even of sculpture, in specimens of the Gonato- 

 piis group. As I have elsewhere stated, in some species, in which 

 when freshly emerged the abdomen is black, after they have lived 

 some davs or weeks, the color becomes entirely f errugnous. 

 Others in which the abdomen is ferruginous, after a week or two 

 become black in color. The color of the antennae and of the 

 thorax and legs is variable in many species, and even the sculp- 



