. THE PEAR THRIPS. we 
Adults may be present in an orchard for a few days and then 
suddenly almost all disappear. This is explained by their habits of 
migration as evidenced by the following observations: In a certain 
pear orchard which had been kept under daily observation for a 
week or more thrips had been abundant in blossoms and buds until 
suddenly one day all seemed to have disappeared. Upon closer ex- 
amination, however, they were found congregating and walking 
around on the larger branches. This was about 3 o’clock in the after- 
noon. On the following morning hardly an individual could be found 
in the orchard. This manner of flight seems to be distinctly migra- 
tory. Thrips often leave their places of feeding just before sunset 
and hover around and over and later settle back on the same trees. 
This mode of flight is decidedly different from the migratory one. 
It occurs only at evening, and the writer has never seen the pear 
thrips in flight during the morning or during the middle of the day. 
DESCRIPTION. 
Euthrips pyri Daniel. 
Measurements: Head, length 0.13 mm., width 0.15 mm.; prothorax, length 0.13 
mm., width 0.2 mm.; mesothorax, width 0.28 mm.; abdomen, width 0.31 mm.; total 
length 1.26mm. Antenne: 1, 334; 2, 45u; 3, 63u; 4, 54u; 5, 33; 6, 664; 7, Iu; 
8, 12”; total, 0.31 mm. Color dark brown, tarsi light brown to yellow. 
Head slightly wider than long, cheeks arched, anterior margin angular, back of head 
transversely striate and bearing a few minute spines and a pair of very long prominent 
“spines between posterior ocelli. Eyes prominent, oval in outline, black with light 
borders, coarsely faceted and pilose. Ocelli are approximate, yellow, margined 
inwardly with orange-brown crescents, posterior ones approximate to but not con- 
tiguous with light inner borders of eyes. Mouth-cone pointed, tipped with black; 
maxillary palpi three-segmented; labial palpi two-segmented, basal segment very 
short. Antennx eight-segmented, about two and one-half times as long as head, 
uniform brown except segment 3, which is light brown; spines pale; a forked sense 
cone on dorsal side of segment 3, with a similar one on ventral side of segment 4. 
Prothorax about as long but wider than head; a weak spine at each anterior and two 
large, strong ones on each posterior angle; other spines are not conspicuous. Meso- 
thorax with sides evenly convex, angles rounded; metanotal plate with four spines 
near front edge, inner pair largest. The mesonotal and metanotal plates are faintly 
striate. Legs moderately long, uniform brown except tibize and tarsi, which are yel- 
low. Spines on tip of fore and middle tibiz weak; several strong spines on hind 
tibiz. Wings present, extending beyond tip of abdomen, about twelve times as long 
as wide, pointed at tips; costa of fore wings thickly set with from twenty-nine to 
thirty-three quite long spines; fore vein with twelve or fifteen arranged in two groups 
of three and six, respectively, on basal half of wing and a few scattering ones on distal 
part; hind vein with fifteen or sixteen regularly placed spines; costal fringe on fore 
wing about twice as long as costal spines. 
Abdomen subovate, tapering abruptly toward the tip from the eighth segment; 
longest spines on segments 9 and 10; abdomen uniform brown, connective tissue 
yellow. 
Redescribed from many specimens, including several cotypes from Miss Daniel. 
Male unknown. 
Food plants: Apricots, apples, almonds, cherries, figs, grapes, pears, prunes, plums, 
walnuts. The insect is found mostly on deciduous fruits. 
Habitat: San Francisco Bay region, California. 
