2i: 



obscure. As however it is so certainly homologous in all genera, 

 tl.ough better developed in some than in others, it must certainly 

 be counted in all where visibly present, or in none. 



It appears to me after a comparative study of the base of the 

 palpi in other Hymenoptera, that what I here count as the basal 

 joint is sometimes considered a true joint by authors, sometimes' 

 as a 'palpiger' or process of the maxilla. In the Dryinidae in many 

 forms there can be no doubt that it is a true moveable joint (as 

 can easily be seen by watching a species under the microscope, as 

 ii. recovers from narcosis), and I must repeat that it is obviously 

 homologous throughout all those genera, in which it can be at all 

 distinguished. I have drawn the palpi of most of the genera with 

 the aid of the camera lucida to show the basal joints, but owing 

 to our isolation these figures cannot be reproduced before the 

 final part of this Bulletin is completed. I may add that it does 

 not appear that the validity of any of the genera described by me 

 v/ould be afifected in any case. Thus it is true that leaving out 

 this basal joint my Chalcogonatopus would have 5-jointed max- 

 illary palps, which is said to be the character o5 Gonatopiis 

 proper, but then the latter has 2-jointed, the former three-jointed 

 labial palpi. 



In Paragonatopus, Haplogomitopus and Epigonatopus only, 

 this short basal joint is apparently absent; and there is there- 

 fore only a single joint before the geniculation in these genera; 

 which also agree in having only a single elongate apical one 

 beyond the geniculation. 



The less specialized forms with large ovate stigma Paraiifcon, 

 Prosanteon and Neochelogynus agree in having six-jointed max- 

 illary palpi, as also do Neodryimis, Chlorodryimis and Paradryi- 

 nns; and all these genera have three-jointed labial palpi. With 

 these latter genera, and in my opinion related to Neodryinns, 

 though apterous, and with the thoracic structure of Gonatopns, 

 must be included C hale ogonut opus, with its similar labial and 

 maxillary palpi. On the other hand, Echthrodclphax with its 

 short maxillary and labial palpi resembles Pscudogonatopns and 

 is obviously allied to this. Indeed I should consider that the 

 latter and the allied apterous genera have been derived from 

 some such form as the Australian Echthrodclphax, while Chal- 

 cogonatopus has arrived at a similar general structure, quite 

 independently, from some such form as the Australian Neodryi- 

 uus; the apterous condition having been accompanied with simi- 

 lar and remarkable changes in the thorax in each case. 



