( 40 ) 



Dr. Perkins had inferred that the 102 species of Odynerus 

 the only indigenous wasps of the islands, had been derived 

 from the ancient immigration from some unknown country, of 

 a single yellow-banded species, and from the much later but 

 still very ancient immigration of a single dark Asiatic species 

 allied to 0. nigripeunis, Holmgr. The latter became extremely 

 dominant, but it found the islands already occupied and 

 only produced a group of 4 allied species, as against the 3 

 genera, the important structural groups and the 98 species 

 which Dr. Perkins recognised in the descendants of the 

 original immigrant. All the species attacked the larvae 

 of Lepidoptera, and the immigration of these must of 

 course have preceded the advent of the earliest ancestor 

 of Odynerus. 



Dr. Perkins showed in his paper how the 102 species had 

 formed Colour-groups in which the constituent members were 

 associated quite independently of affinity. Thus the species 



[lvii 

 of a genus, or of a definite Structure-group within the 

 genus, were found in different Colour-groups in the differenl 

 islands, and sometimes even within the limits of a single 

 island. 



Although i he species of Odynenis were the dominanl 

 members, some of the Colour-groups also contained be< 

 which tin' 53 species in the single genus Nesoprosopia, were 

 traced to a probable single Asiatic immigrant, allied t<> 

 Prosojiis kriechbawm I I ; and Fossores (Crabronidae), of 

 which the 18 species and 3 geuera were believed to have arisen 

 from a single Asiatic invader, allied to Crabro vagus, L. The 

 main Colour-group also included Ichneumonids. 



In illustration of the paper, Prof. Poulton exhibited the 

 specimens referred to in the following letters written to him 

 by Dr. Perkins, Nov. 2 and Nov. 4, 1911, but here combined. 

 The Colour-groups were arranged in the order of the islands, 

 from Kauai in the N.W. to Hawaii in the 8.E. The authors' 

 names had been added by Prof. Poulton. 



" Herewith I am sending a small box of Hawaiian Hymeno- 

 ptera. showing the main colour-effects.* 



* Dr. Perkins wrote Nov. 13, 1911 : — " The characteristic appearance of 

 the various groups is far more remarkable in masses of specimens, such as 

 I have in my cabinet drawers, than in a few isolated specimens." 



