xv iii INTRODUCTION. 



name to a species that another has the task of describing;, may 

 for this purpose publish previously a short diagnosis under his 

 name in any journal. 



\ion relative I" the Types in Description. 



In insects in general, the female represents the type of the 



i es- Though, in exceptional eases, the male may be the 

 larger, the more beautiful, ami at times with unusual appendages, 

 he remains always more variable than the female. Among the 

 Bymenoptera, the males have hardly any other part to play than 

 a passive one; the other sex it is, which alone develops that 

 remarkable activity which manifests itself in the interesting 

 habits of these insects. The females are larger and more 

 stable in their forms and colors. The slightest examination 

 renders it apparent that it is among the females the type of the 



ies is to be soughl for, and by no means among the males. 

 In the Vespidse, especially among the .Solitary Wasps, the males 

 are small and variable ; at times, one would be inclined to con- 

 sider them as abortions; they do not oiler us good differential 

 sties as the females, and tbey are to be determined 

 only by the tentative method in referring them "de visu" to their 



ctive females. 

 There exists a number of species of which the males resemble 

 each other bo far as nol to be distinguishable. This may be seen, 

 for instance, among certain Odynerus, but it is especially among 

 the Scolia that this phenomenon appears in all its intensity. 

 There ia a whole category of species in the genus Elis of which 

 the female, offer differences the most extreme, but of which the 

 males are so confounded that they cannot be distinguished from 



other. What is most remarkable on this score is, that these 

 ■ to be found spread over every continent, and that 

 each continent numbers several of them. Thus: 



America : Elis plumipes, limosa, trifasciata, dorsata, etc. 

 Africa: s collaris, capensis, elegans, ofricana, fascia- 



tella, etc. 



Ihoracica, annulata, marginella, limbata. 

 Australia: Elis ra Ma, Z-cim ta, etc. 

 Europ villosa. 



