48 



MISCELLANEOUS EESULTS OF WORK OF BUEEAU — IX. 



deeply notched behind eyes; eyes red, made up of a few large facets, surface faintly 

 reticulated ; head rounded in front; a pair of setae over rear angle of eyes, another pair in 

 front of the eyes, and a third over the antennae. Antennae translucent, extending 

 forward about twice the length of the head and composed of 7 segments; first segment 

 cylindrical, broader than long; second cylindrical, nearly twice as long as segment 1 

 and not so broad; third longer than second, base constricted but not pedunculate, and 

 with constriction at third and two-thirds length from base, so that it appears to be made 

 up of 3 segments; fourth spindle-shaped, about as long as third; 5, 6, and 7 short and 

 slender and not very clearly defined. Segments bear few spines on sides. 



Prothorax nearly one-half again as wide as long, sides rounded, posterior edge broad- 

 est, semitranslucent white to faint yellow, a few jirominent setae around edges. Meso- 

 thorax with prominent rounded angles, translucent white to faint yellow, surface 

 faintly reticulated, wing-cases translucent white, distinct from each other, those of 

 fore- wings extending to second abdominal segment and those of hind- wings extending 

 to middle of second abdominal segment. Legs translucent white to faint yellow, strong. 

 A])domen shaped as in adult, white to faint yellow, last few segments translucent, eight 



rows of setae in pairs, increasing in length 

 from anterior to posterior end. Length of 

 abdomen, 0.5956 mm. 



The full-grown nymph or pupa (fig. 17, at 

 right). — Length, 1.25 mm.; width at meso- 

 thoracic angles, 0.2812 mm. Shape similar 

 to that of adult. Color translucent white 

 to slightly yellowish. Head, length, 0.1628 

 mm.; width, 0.1924 mm.; translucent 

 white, distinctly reticulated, eyes dark red, 

 larger than in prepupal stage, facets large. 

 Three ocelli present in close triangle be- 

 tween eyes, color chitinous yellow. An- 

 tennae laid backward on head and reach- 

 ing to near middle of prothorax, segments 

 indistinct, translucent white. Segments 



1 and 2 projecting in front of the head and 



2 with a long spine extending forward, 

 0.1332 mm. in length. Thorax plainly 

 reticulated, translucent white to faint yel- 

 low. Prothorax more than twice as broad as long. Wing cases 0.4736 mm. long, 

 extending to near middle of fifth abdominal segment, translucent white to faint 

 yellow. Length from head to end of wing-pads, 0.6512 mm. Legs translucent white 

 to pearly white. Abdomen broader and shorter than in adult, contracted, but of same 

 general shape, surface plainly reticulated, setae well developed, the longest ones at 

 posterior end. Length of abdomen, 0.6956 mm.; width, 0.3552 mm.; length of 

 posterior setae, 0.0888 mm. 



HABITS OF THE ADULT. 



After emerging from the pupae, the mature thrips feed on the under- 

 side of the leaves for several weeks. They are not, as a rule, as abun- 

 dant on the upper surface. One plant, on which there were about 

 150 adults, had only 3 or 4 of this number feeding on the upper sur- 

 face of the foliage. 



Adults walk over the leaf quite rapidly, and if disturbed they raise 

 the tip of the abdomen and move rapidly away, walking in any direc- 

 tion. In a few cases they have been observed to jump when dis- 



FiG. 17.— Greenhouse thrips: Prepupa on the left 

 and pupa on the right. Enlarged about 40 

 diameters. (Original.) 



