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PLATE III. 



By the Rev. O. P. CAMBRIDGE, M.A., &c. 



JNE of the most interesting, and at the same time 

 most unaccountable, experiences in entomology 

 is the sudden or unexpected occurrence of species. 

 Years mil pass by and insects which have been 

 long unseen, all at once without any assignable 

 cause, put in an appearance, sometimes in great 

 abundance, and then for many years again almost, or altogether 

 disappear. Nearly akin to this, and quite as interesting and 

 unaccountable, is the occurrence for the first time of a species 

 within any well-defined geographical area. Many instances Of 

 this might be mentioned as having occurred within the memory 

 of living Entomologists, but perhaps the most recent is that 

 which is the subject of the present notice. Yarious reasons 

 might be, and often are, suggested why the particular species 

 may have long existed in the new locality, and have been over- 

 looked. The locality may not have been worked by anyone 

 jikely to have noticed it ; or the species may have been passed 

 over as identical with some other one nearly allied ; or the par- 

 ticular specimens met with may have been blown over in some 

 abnormal gale of wind ; or the eggs, or pupao or even the perfect 

 insect may have been accidentally or designedly introduced. All 

 these and similar suggestions must of course be tested according 

 to the evidence or probability in each instance ; and each is of 

 course quite possible ; but after careful consideration of the cir_ 



