xlv 



In this manner five other pairs of species are associated together 

 by Dr. Adler — 



Neurotenis fumi]}ennis with Spathogaster albipes 



„ numismatis ,, „ vesicatrix 



Dryophanta scuteUuris ,, Trigonaspis megaptera 



,, longiventris „ Spathogaster Taschenbergi 



Ap)hilothrix radicis ,, Andricus noduli 



Mr, Cameron insists that if such associations were true the two 

 supposed species of each pair would appear in the same localitj'. 

 An examination of what is known of these five supposed dimorphic 

 species proves, however, that of the first four pairs the individuals 

 are not found in the same localities, whilst of the last pair, although 

 admitted by Mr. Cameron to be " undoubtedly found together" 

 (that is, in the same locality), he has no hesitation in saying that 

 they are by no means related in the way stated by Adler, D. longi- 

 ventris being also pretty common in this countrj'-, whereas its 

 supposed double, S. Taschenbergi has not yet been found here. 

 Of A. radicis it has been full}^ proved that there is only one brood 

 in the year, whilst the galls of its supposed double, A. noduli, 

 appear in the spring, and the insects quit them in the autumn. 

 Thus this pretty German theory is blown to the winds by the 

 direct and well-continued observation of facts. 



A curious phenomenon is mentioned hj Mr. Cameron with one 

 or two of the polvthalamous gall-makers — namely, that from 

 one gall only females will be produced, from another only males, 

 but oftener both sexes will be found in the same gall. This 

 observation has a very curious bearing on the variations of 

 parthenogenesis, termed by Leuckart " Arrenotoky," and by 

 Siebold " Thelytoky." The fact, however, of the existence of 

 parthenogenesis has been fully proved by Mr. Cameron, not only 

 in the Cynipidce, but also in the Tenthredinidce, of which numerous 

 instances are given in the article under notice. 



An article on the alternations of generations in the Cynipidce, 

 by M. Lichtenstein, appears in the ' Scottish Naturalist,' July, 

 1877. 



Mr. Riley's memoir on Nematus ventricosus, contained in his 

 ' Ninth Report,' makes us acquainted with the interesting fact 

 that that species is subject to the variation of parthonogenesis in 

 which male progeny only are produced l)y unimpregnated females, 



