15 



POPULAR PAPERS ON ENTOMOLOGY. 



THE OAK-PRUNERS : ELAPHIDION PARALLELUM, Newm, AND PHYMA- 



TODES VARIABILIS, Fab. 



BY C. H. T. TOWNSEND, CONSTANTINE, MICH. 



In last year's Report I noticed with interest the article by Mr. Clarkson on Elaphidion 

 vittosum, Fabr. I have reason to believe that the same is partly the case also with E. 

 parallelum, Newm., which I find to be the common oak-pruner here. But I do not agree 

 that it is always, or even in the majority of instances, the case with either species. As 

 bearing on this subject E give the following extract from my notes for 1885, which relates 

 also to Phymatodes variabilis, Fab. : — 



" Last fall (Sept.) I laid in a large supply of red, white and black oak and hickory 

 twigs, containing larva? of oak-pruners. The majority were red oak and hickory, but all 

 were kept in separate boxes. Also a large box full of sawed hickory wood which contained 

 wood-boring larva?, These were all kept regularly moistened. During May and June, as 

 I was absent from home at the time, another person, a lady, collected and saved for me a 

 bottle full of beetles from the vicinity of these boxes (all taken from and around the large 

 box of hickory wood, she says). These I afterward examined, and found the bottle to 

 contain 145 Phymatodes variabilis, Fab., and 18 Elaphidion parallelum, Newm., besides 

 two Tenebrionidce of uncertain origin. As to which the two species proceeded from, the 

 twigs or the hickory wood, the lady, who examined the twigs from time to time without 

 being able to discover a single specimen among them, is almost certain that they all came 

 from the large box of sawed hickory, on the underside of the papers covering which she 

 was able to pick them off in large numbers, as well as all over and around the box and on 

 the wood inside. Upon examining a good number of the twigs of each kind later in the 

 season, I found not an insect in them (with the exception of one which contained a dried 

 and shrivelled larva that had not transformed), but they showed every sign of the insects 

 having emerged as perfect beetles. The E. parallelum, Newm., must have come from the 

 twigs, while the P. variabilis, Fab., all proceeded from the sawed hickory wood. Packard 

 gives the latter species as living only in white oak, but I am confident that these came 

 from hickory, though I cannot conceive what became of the other numerous Elaphidions 

 which must have emerged from the twigs." 



In my notes for 1884, under date of 18th September, I extract also the following: — 

 '■' Found an oak-pruner in the pupa state, inclosed in its silken white cocoon, inside a red 

 oak twig. The end of the twig was not closed up, as is usually the case, but the passage 

 was open, and a couple of inches up from the end the larva had changed to the pupa state, 

 leaving its cast ofi skin below it in the passage." 



Upon reading the account by Dr. Fitch, of E. villosum, Fabr., I find he says that 

 " some of the worms enter their pupal state the last of autumn, and others not till the 

 following spring. Hence, in examining the fallen limbs in the winter, a larva may be 

 found in one, a pupa in another." Now, though I have found the pupa of E. parallelum, 

 Newm., very early in the fall (18th Sept., as stated above), and Mr. Clarkson has found 

 the imago of E. villosum, Fabr., in November, I am inclined to think that these early 

 metamorphoses were from eggs deposited earlier than others, or that by some favourable 

 circumstances these individuals developed more rapidly and thus metamorphosed earlier 

 It is my opinion that both these species may assume the imago state either in the fall or 

 the following spring, some, more forward than others, attaining this state in the fall. 

 Perhaps favourable years, when some of the eggs may be deposited earlier in the summer 

 than usual, produce the autumn imagos, which then remain within the twigs during the 

 winter and emerge early in the spring. These in turn, if the season is at all favourable, 

 will lay their eggs earlier than Mie others, and thus continue the early metamorphosis. 



