189 



Dune. Opening cocoons of this moth, whose larva had been at- 

 tacked hj the Hymenopteron, the cocoon of the Ophion is seen with- 

 in the innermost cocoon of the moth, with the dried larva-skin of the 

 Saturnian shrivelled up and fitting closely to one end of the cocoon, 

 just as in uninjured specimens it lies against the extremity of the ab- 

 domen of the pupa. The larva of Hyalophora, with the parasite 

 within it, must then live until after it had made both of its cocoons, 

 and die before changing to a pupa ; the larva of the Ophion at this 

 time must be prepared for its transformation, and, making its cocoon 

 within the larva, transforms to a pupa ; the Saturnian larva dies, — a 

 mere pellicle expanded over the enclosed cocoon of the Ichneumon ; 

 the skin dries, contracts, splits at the usual place, and shrinking, just 

 as it would have done in its normal condition, over the enclosed pupa, 

 is gathered into a cup-shaped parcel at the end of the cocoon. 



Capt. N. E. Atwood, of Provincetown, Mass., gave an account of the 

 changes the fisheries of our coast had undergone, and of the variable 

 habits of many species of fish. Early accounts state that up to 1 764 

 blue-fish (Temnodon saltator Cuv.) were very common north of Cape 

 Cod, after which date they disappeared. Having had an experience 

 of forty years in connection with the fisheries, he could say that none 

 had been seen north of Cape Cod until twenty-five years ago, when 

 he saw his first blue-fish. Those found at that time were invariably 

 small, the largest weighing about two pounds. In 1839 they were 

 caught ofi Nantucket weighing eight to ten pounds ; in two or three 

 years more those coming north of Cape Cod were larger, and drove 

 away the mackerel and smaller fishes, and completely filled Province- 

 town hai'bor. They are found now in great abundance. They make 

 their appearance in June, coming into the harbors all at once, and 

 driving away the mackerel entirely. On one occasion they came on 

 the 22d of June ; the day pi-evious 8,000 mackerel were caught in the 

 harbor ; on the 22d not one was to be found. They leave the coast 

 with the appearance of the first cold northeast storm, about the last of 

 September, though two or three individuals were taken in Province- 

 town last December. They have only recently come into the market, 

 for seven years ago scarcely any were sold ; but during the past 

 season he alone had brought to the market 45,000 pounds weight. 

 Since their great increase, the lobsters {Homarus americanus Dekay) 

 had multiplied four-fold, for the natural enemies of their young had 

 been driven away by the blue-fish. Formerly these fish appeared in 

 large shoals near the surface, constantly " flouncing out " of the wa- 

 ter, and they were caught in sweep seines and by the hook ; now, 

 though they come in large quantities, they seem to prefer the deeper 

 waters. This year he had not seen a dozen " flounce out " as former- 

 ly, nor can they be taken, as then, with the hook. Another mode of 



