Aug. 6,1917 Two New Cambium Miners 315 



stem is black, cylindrical, and the end is very faintly dented where it articulates 

 with the anterior portion. From the posterior end of this stem are two long, flat, 

 chitinous blades which are much longer than broad. They are dark brown above 

 and black on the lower edge where they are slightly more chitinized. The muscles 

 appear to be attached to the inside surface of these blades. On the underside, where 

 the two large blades branch out from the stem, is a fingerlike projection, pointing 

 backward. This projection is hollow and U-shaped and is divided at the apex. It is 

 brownish above and black on the underside. For fiulher details see Plate 48, A, a. 



Along the upper front edge of the first segment next to the head there are small, 

 impressed, parallel lines and the lower portion is covered with numerous, very short, 

 yellowish brown spines. On the dorsum of this segment, just in front of the middle, 

 are located the anterior spiracles; they are T-shaped, yellow and very faintly raised 

 above the surface. From a dorsal view they have about 8 or 10 microscopic ring- 

 lets around the edge, giving the edges a scalloped appearance. Back of these 

 spiracles is a faint depression formed by a transverse fold or wrinkle. The segmental 

 lines are rather weak and the segmentation can be plainly seen on the plate. Along 

 the basal segmental line of the last segment are three rows of microscopic, yellow, 

 chitinous plates; the first row (toward the head) is broken on the dorsum only, the 

 middle one is broken on the dorsum and venter while the third row is just a short 

 row on each side. Just below the middle of the last segment are three short rows of 

 the same plates on each side of the larva. The posterior spiracles are situated on two 

 tubercles located on the dorsal, apical portion of the last segment. These tubercles 

 are pale yellow and flattened along the apex. On this apical edge are three brown, 

 nearly roimd, chitinous plates, each having a transverse dorsal slit. For details see 

 Plate 48, A, b. On the ventral side near the apex is a large tubercle with the anal 

 opening located on the apex. 



Average length, 15 to 17 mm.; average diameter, 0.75 to i mm. 



The pupa (PI. 48, B) is pale yellow, cylindrical, and tapers very slightly toward 

 each end. It is faintly shiny and is formed by the shrinkage of the larva. The head 

 is entirely retracted, leaving 11 segments plainly visible. All segments are marked 

 with well-defined grooves. The entire siuiace of the pupal case is faintly marked 

 with transverse striae. All the segments are nearly uniform in width except those on 

 each end, which are narrower. The place where the head was retracted is marked 

 by a small puckered surface, faintly reddish. The anterior and posterior pairs of 

 spiracles are formed by the shrinkage of those of the larva into small reddish brown, 

 chitinous tubercles. The anal area is marked by a circular depression which is 

 nearly black in the center. The adult emerges through a slit made along the lateral 

 edge of the first three or four segments. 



Length of male, 4 mm.; diameter, 1.65 mm. Length of female, 5 mm.; diameter, 

 2 mm. 



SEASONAI^ HISTORY 



During July and August the larvae were fairly common at Falls Church, 

 Va., and the surrounding country. They mine down the cambium in 

 the trunk and roots of Acerrubrum, and, after reaching maturity, make 

 their exit, pupating in the ground about 32 to i inch to the side of the 

 exit hole. Full-grown larv'^ Vvcre collected from July 10 to August 19 by 

 Mr. T. E. Snyder and the writer. Full-grown larvae were also taken 

 at French Creek, West Virginia, on July 11, 1916, by Mr. F. E. Brooks. 



Pupation took place from July 10 until the latter part of August, and 

 the species remained in the pupa stage during the winter. 



Adults emerged from April 24 to 26, 191 6. 



