THE JUMPING PLANT-LICE OR PSYLLID^ OF THE NEW WORLD. 145 



Described from numerous males and females from Ithaca, New 

 York, and several other near-by localities; collected from May to 

 August of several years; and many from Detroit, Michigan (Hubbard 

 and Schwarz), October 7. 



Distribution. — Introduced from Europe into Salisbury, Connecticut 

 (1832); spread subsequently into Massachusetts and New York; 

 recorded later from Illinois (Le Baron), Michigan (Schwarz), (see 

 Slingerland '92:162); Ohio (Webster); New Jersey (Smith), (see 

 Lintner '93 : 325) ; Maine (Patch '11: 11); "southwest to Maryland and 

 Virginia" (Sanderson — Insect Pests of Farm, Garden, and Orchard 

 1912:641); California (Essig. Mon. Bul.Cal. Comm. Hort.2:43; 1913), 

 the latter is doubtful. 



Distribution outside of America: Great Britain, Gallia, Germany, 

 Austria, Hungaiy, Transcaucasia, Akstafa (Oshanin '07:352); Japan 

 (Ku way ana '08:163). 



Food 'plant. — Pyrus communis (common pear), on which it is very 

 destructive and of great economic importance; reported on Pyrus 

 malus (apple) to a less extent -in Europe, but not in America. 



Life history. — Eggs. — The eggs are deposited about the middle of 

 April by the females which have passed the winter in hibernation; 

 they are light yellowish in color, ellipsoidal, with a short attachment 

 pedicel at large end and a slender filament at small, free end; deposited 

 singly or in rows of five to ten in cracks and creases in the bark, or in 

 old leaf scars at the bases of the terminal buds of the preceding 

 year's growth. 



The eggs hatch in from eleven to thirty days, according to the 

 temperature. The hibernating adults disappear about the time most 

 of the eggs have hatched. 



Nymph. — First instar. — Oval, pale, translucent yellow, abdomen 

 darker, eyes reddish ; abdomen fringed with several long hairs ; wing 

 pads not distinguishable; antennae three-jointed; length about 0.37 

 mm. 



Second instar. — First molt about six or seven days after hatching; 

 size one- third larger; color practically unchanged; antennas four- 

 jointed; wing pads begin to appear. Second molt in four days. 



Third instar.— Length 0.77 mm. Wing pads blackish and thoracic 

 markings begin to appear; antennae six or seven jointed. Third molt 

 three days later. 



Fourth instar. — Full-grown nymph; length 1.4 mm.; width 1.15; 

 oval, flattened; general color light yellowish brown, marked with 

 blackish; wing pads, distal half of abdomen, head except a mesal 

 light stripe, several bands and spots on thoracic and basal abdominal 

 dorsum blackish or brown; a number of long, stout, spine-like setae 

 project from margin of body. 



