118 RAY AND SOME OF HIS FELLOW-WORKERS 



Willugliby's account of the ichneumon of the cabbage 

 butterfly is given. Some of the caterpillars are said 

 to have produced, not ichneumons but flesh-flies 

 (Tachinidse?). Eay and Willughby remarked the 

 similarity of the ichneumons to ants and gall-flies. 

 They are cautious about drawing conclusions from what 

 they thought they had seen. " De his nobis nondum 

 satis perspectis nihil temere pronunciare audemus." 

 Another season they would make more careful observa- 

 tions. A few years later we find Martin Lister ^ quite 

 clear that ichneumons are bred from eggs laid in cater- 

 pillars or the eggs of spiders by flies of the same species. 

 Willughby^ thought Lister's explanation ingenious and 

 true, but desired fuller proof. 



The Androgyny of Snails 



Under Deadly Nightshade Eay observes that the 

 poisonous properties of this plant do not keep ofi" snails 

 and slugs, and goes on to say that these moUusks are 

 androgynous. The details which he mentions leave no 

 doubt that he had witnessed and understood the re- 

 ciprocal union, of which he says that neither Aristotle, 

 nor, so far as he knew, anyone else had made mention. 

 Seven years later Swammerdam noted the same remark- 

 able fact, which he further elucidated by dissection f he 

 was ignorant at this time that he had been anticipated 

 by Ray; it was not to be expected that a discovery 

 relating to snails would be found in a catalogue of 

 Cambridge plants.* The Biblia Natures contains excel- 

 lent figures, with a full description. 



1 Phil. Trans. 1671 ; Translation of Goedart (1682). 

 ^Phil. Trans. 1671. ^ De respiratione, p. 117 (1667). 



* Swammerdam's Historia Insectorum Qeneralis (1669) recognises Bay's 

 priority. 



