374 REPORT OF THE COMMISSIONERS OF 



according to the observations of Dr Fitch, but it would seem very probable that 

 oviposition may occur much later, as the beetles are abroad till into August. The 

 attack usually begins at the base of the tree. The young grub works its way under 

 the bark and begins feeding upon the tissues and making a serpentine burrow. The 

 boring increases in size with the growth of the larva and in the course of time the 

 tree may be completely girdled and then it must soon die. Dr Packard, writing in 

 1870, calls attention to finding three sizes of larvae and I have found it comparatively 

 easy to separate those taken from a badly infested piece of limb in a similar 

 manner. 



Food plants. This insect appears to infest the white elm almost exclusively, 

 though Dr Fitch records it as breeding in the slippery elm. I have seen no indica- 

 tions of it attacking the English or Scotch elms, so common in Albany. There is a 

 record of this species having been reared from maple, but it would seem that the 

 infestation must have been accidental. 



Associated insects. Two species of curculionid or snout beetles may frequently 

 be observed working in elms attacked by this pest, but they appear to follow and 

 not to initiate an attack. Magdalis armicollis Say and M. barbita Say are both small 

 beetles a little over a quarter of an inch long, the former reddish and the other black 

 (Plate 3, figures 5, 6, and 6a). They are closely allied and the grub shown at figure 

 7 might well represent either species and the same is true of figure 8, which illus- 

 trates a pupa within its oval cell. The pupal cell is shown at figure 8c? and the bur- 

 rows of these insects at figure 9. The larvae of these species transform to pupae by 

 the last of May, the beetles appearing in large numbers at this time. These insects 

 apparently require but one year to complete the life cycle. They usually occur in 

 the smaller limbs above where Saperda has been working but as this latter insect 

 begins near the base of the tree and works up, it frequently occurs that the two 

 species are found working together, as represented on the elm block figured on 

 plate 3. These little beetles sometimes occur in immense numbers and then they 

 are liable to parasitic attack. The following insects, most probably parasites of 

 Magdalis, were bred from material in badly infested limbs. Brachistes {Calyptus) 

 magdalis Cress., Entclus onerati Fitch, Smicra micregaster Say, a Pteromalid and a 

 fly, Limosina crassimana Hal. The cocoons of an ichneumon parasite, Melanobracon 

 simplex Cress., occurred in numbers under the bark where Saperda larvae were abun- 

 dant, on which the insect preys. 



Another ally of Saperda, Neoclytus erythrocephalus Fabr., is less common than 

 the two species of Magdalis. This is a small reddish beetle about three-eighths of 

 an inch long and prettily marked with three yellowish, nearly transverse lines on 



