1040 The Zoologist — January, 1868. 



may feed on the same leaf, and may never wander from the same 

 garden. I do not say that these conditions are necessary, but merely 

 that the pairs will unquestionably bear the test of the most rigid 

 restrictions to similar conditions. The examples I select are by no 

 means the best I could find. No. 1 I have chosen on account of a 

 peculiar interest attached to the discovery ; the other nine because the 

 abundance of the individuals in each case affords the inquirer such 

 ample opportunity of testing the soundness of my views. 



1. Bomhyx Spartii and B. familiar is. — During the summer which 

 has just passed away my friend Mr. Doubleday sent me the larva of a 

 Bombyx which he had received from the Continent under the name of 

 13. Spartii, which was totally different from any larva I had pre- 

 viously seen : M. Guenee had previously described both the larva and 

 imago of Bombyx Spartii, and this was the larva in question. Hubner 

 had previously figured tlie imago : Boisduval had both figured and 

 described it ; and Herrich-Schreffer describes it in his ' Systematische.' 

 Our countryman Stephens makes five British species out of the section 

 of Bombyx now under consideration, three of which, Rubi, Trifolii and 

 Quercus, he considers good and veritable species; two others, Medi- 

 caginis and Roboris, he places within brackets, thus implying a doubt 

 whether they be really species ; under Roboris we find the Bombyx 

 Spartii given as a variety, with references to Hubner's figures of both 

 sexes : thus it appears from this, that Mr. Stephens, the most species- 

 making of all entomologists, raises Bombyx Spartii to no higher rank 

 than the variety of a variety, and it may be added that no permanent 

 character has been pointed out whereby its imago can be distinguished 

 from that of the insect I have next to notice. 



Bombyx familiaris is anew name: it was Bombyx Quercus, and 

 also familiarly known in England as the " Great Oak Eggar." The 

 reason for the change of name is simply this, that our familiar insect 

 is not the Bombyx Quercus of Linneus : we all know from the original 

 description, from the habitat and from the Linnean specimen still 

 extant, that the name of Quercus belongs of right to the insect we have 

 within the last dozen years rechristened under the name of Calluua?. 



The larva; of Spartii, to which I have just alluded as received by 

 Mr. Doubleday from France, underwent their metamorphosis and 

 emerged as perfect insects in all respects identical with our familiaris. 

 The larva) are totally distinct, the moths perfectly identical. 



In this as well as in the instances which follow, we must adopt one 

 or the other of these two conclusions : Jirst, that two perfectly distinct 



