94 



had to make were, of necessity, to a great extent of a comparative 

 nature. Moreover the time that has elapsed has allowed of some 

 further investigation of the subject, the result of which, I think, 

 may prove of assistance in its consideration. 



Dealing first with the question of geographical distribution, it 

 will be desirable to fix the boundaries of the insect's range with 

 some amount of exactness ; this, however, is at all times a matter 

 of some little difficulty. If a species is taken in a particular place, 

 we have, in the fact of the capture, direct evidence of the oc- 

 currence of the species in that district ; but the fact that it has not 

 been observed is no evidence that it does not occur ; therefore 

 in attempting to define its range we must be guided, to a large 

 extent, by what I may term presumptive evidence, by which I 

 mean the probability of one set of known facts harmonising with 

 other sets of equally well-understood circumstances, or the reverse. 

 Fortunately the habits of T. comes are sufficiently well known, and 

 we have records of its presence from places sufficiently near to- 

 gether to form a fair working basis. 



Throughout Central and Southern Europe we have abundant 

 evidence of its presence, the most easterly records being Amasia 

 in Asia Minor, a few miles south of the Black Sea coast ; Eibes, 

 at the foot of the Taurus Mountains, in the same country, and just 

 north of the Mediterranean ■ and Beyrout, on the Syrian coast. 

 Possibly its range may extend some short distance further eastward ; 

 but having regard to the proximity in that direction of the vast 

 tracts of desert lands and mountain ranges, coupled with the fact 

 that we do not find the species represented in collections from 

 Central Asia, we must conclude that we have reached the borders 

 of its eastern range. The available information as to its southern 

 limit is hardly so satisfactory. That it occurs along the northern 

 shores of the Mediterranean and extends into some of the Greek 

 islands there is no doubt ; it is also credibly reported from the 

 North African coast ; but it is probable that it does not extend far 

 south from the Mediterranean, for here again the vast sandy desert 

 that stretches almost from the Atlantic seaboard to the Red Sea 

 would no doubt check its progress in this direction. It was also 

 included in the older Canary lists ; but this last record appears to 

 be open to grave doubt. The Lepidoptera of the Canary Islands 

 have of late received considerable attention, and some few collec- 

 tions made there have from time to time been sent to this country ; 

 but, so far as I can learn, there were no T. comes in them. The 

 species appears to have been included in the older lists on the 

 authority of Brulle ; but in the more recent literature on the 

 Lepidoptera of the Canary Islands it is assumed that he was led 

 into error by a small T. proiiuba, a species that appears to be 

 represented in greater or less numbers in every collection made in 

 the islands. The Atlantic Ocean forms its natural western boundary. 

 As to the northern limit of its range we have some precise and 



