84 PSYCHE [April 



By dropping the pupa into xylol for a few minutes to clear and dissolve off the 

 wax, and then mounting in xylol balsam, the surface structures can be plainly seen. 



A pair of short caudal setae arise from minute papillae, barely within the caudal tnargin. 

 A still smaller pair arise one on each side, a short distance from the first pair on caudo- 

 lateral margin. Vasiform orifice subovate, one fourth longer than broad, indented poste- 

 riorly. Corrugations or folds extend downward and inward from sides of orifice. Oper- 

 culum very broadly ov^ate, extending a little more than one half the distance toward caudal 

 end of orifice. Lingula spatulate, setose, bearing distally three distinct side lobes on each 

 side and a single terminal lobe. All except terminal lobe and posterior pair of side lobes 

 covered by operculum. From each side of terminal lobe a rather stout seta arises extending 

 caudad nearly to apex of orifice. On cephalic region about one fifth of distance from ceph- 

 alic to caudal margin is a pair of spines, one on each side of middle; on first abdominal 

 segment a second pair, one on each side ; and near vasiform orifice, opposite the widest 

 part, a third pair of spines, one on each side. These three pairs of spines are all simple, 

 minute, and of about equal size. Extreme margin irregularly radiately striated. A short 

 distance mesad from margin is a row, all around, of small conical projections or thickenings 

 and mesad to these, a row of minute knobbed setae. The structures of the inner row as a 

 rule correspond in number and position to those of the outer row. Mesad to these two 

 rows, body loses its striated appearance and is somewhat rugose. On each side of middle of 

 dorsum are the circular pores already mentioned. As a rule these never occur nearer the 

 margin than a distance equal to one fifth width of body. There are about twenty-seven 

 pairs of these, and almost invariably several unpaired ones also occur, particularly on 

 cephalic region. Near each pore is a minute knobbed seta similar to those near margin of 

 body. There are about fifteen or sixteen pores on cephalic region, those most anterior being 

 usually unpaired; there are usually four pairs on mesothoracic region, four pairs on meta- 

 thoracic region, two pairs on first abdominal segment, one pair on second, and two pairs 

 each on the five following segments. On the under side of body the short and stout legs 

 and antennae can be plainly seen. Antennae lie in pockets outside of first pair of legs, are 

 stout, near the outer end abruptly narrowed, forming a slender tip. 



Adult 5. Length 1.-1.2 mm. Color, pale yellow, becoming covered with white flour- 

 like substance a short time after emerging from pupa case. Rostrum usually tipped with 

 black. Wings immaculate, about i.i mm. long, and .48 mm. broad, with a single 

 unbranched median vein ; on margin are globular beads which bear on outer side several 

 minute setae. Eyes divided into two parts; color, dark red. Legs and antennae of 

 specimens mounted in xylol balsam nearly colorless. Segments of antennae show following 

 proportions with eyepiece-micrometer, one-inch eyepiece, and one-half-inch obj. : 2-5-11-3- 



42-4-3i 



Adult $. Length .9 mm. Proportionally smaller than J, otherwise diftering only 

 in sexual organs. 



This is a common species in this locality (Amherst, Mass.), occurring abun- 

 dantly on several species of Spiraea. I have also found it though less frequently 

 on strawberry with Aleyrodes packardi. 



I take pleasure in naming this insect for Prof C. H. Fernald who first called 

 my attention to its occurrence on Spiraea growing on the college grounds. 



