35 



A New Enemy of the Black Spruce, Abies Nigra. 

 By Dr. H. A. Hagen, Cambridge, Mass. 



An enemy of Abies nigra sent to me by Mr. C. S. Sargent, from the Arboretum of 

 Harvard University, induced me to compare the literature about the enemies of this tree. 

 To my surprise, all that is published consists of two very excellent papers by Mr. Ch. H. 

 Peck, Albany. One, "The Black Spruce," read before the Albany Institute, May 4, 

 1875, 8v., pp. 21 ; the other in the New York State Museum's Report of the Botanist, 

 No. 30. I do not remember to have seen these papers recorded in entomological serials. 

 There are noted two vegetable parasites, Arceuthobium pusillum and Peridermium decolo- 

 rans. Of insects are recorded a plant-louse near Adelges coccineus,&rid some Hemipterous 

 gall imsect ; also, two beetles, Hylurgus rujipennis and Apate rujipennis. 



The twigs sent to me contained numerous pale spots, the consequence of some dead 

 leaves, three or more, one near the other. The examination of those leaves showed on 

 every one at the base, sidewards, a small round hole. The interior of the leaf was hol- 

 low, in some cases only the lower half, where the enemy had not yet finished the work. 

 I discovered directly a small caterpillar, belonging to Tineidse and probably to the Argy- 

 resthians, as the destructive enemy. The biological collection contains no enemy of the 

 black spruce, and no similar destruction of pines, except a somewhat related twig of 

 Pinus Canadensis, quoted also as probably done by an Argyresthian larva. In Mr. 

 Chambers' valuable list no Tineid living on spruce is recorded. 



The European literature contains only one fact similar to the American. It is re- 

 corded that Cedestis farinatella hollows the leaves of pines. But until now no American 

 species of Cedestis is known. Probably the moth will be raised and the mystery solved; 

 at all events, T desire to draw the attention of entomologists to this enemy. Perhaps it may 

 be more common than is supposed, Prof. Peck stating as a fact that the spruce trees in 

 some parts were said to be dying at an unusual rate, as if affected by some fatal disease. 

 To judge by analogies, the attack made by Hylurgus and Apate is only a consequence of 

 the previous attacks by other enemies. 



Notes of the Swarming of Danais Archippus and Other Butterflies. 



While spending the winter of 1875-76 in Apalachicola, Florida, I found one of these 

 archippus swarms in a pine grove not far from the town. The trees were literally fes- 

 tooned with buttterflies within an area of about 

 an acre, and they were clustered so thickly that 

 the trees seemed to be covered with dead leaves ; 

 fig. 14 will enable the reader to form some idea 

 of their appearance thus grouped. Upon shak- 

 ing some of the trees a cloud of butterflies flew 

 off, and the flapping of their wings was distinctly 

 audible. They hung in rows (often double) on 

 the lower dead branches, and in bunches on the 

 needles. I find by my note book that visiting 

 the flock towards evening, it was receiving ad- 

 ditions every moment. I caught a net full off 

 a bunch of dead needles, and walking away to 

 some distance and letting them go, all but three 

 returned to the flock. The question as to where 

 they came from seems a very interesting one. I 

 was told by Dr. A. W. Chapman that there was 

 hardly milkweed enough in all Florida to produce one of these flocks, which doubtless 

 do not confine themselves to Apalachicola. During my visit I found two more flocks 



Fig. 14. 



