152 pROCEEDINOS OF THE NATIONAL MUSEUM. vol. xxvi. 



ciiiulal end of abdomen. The wing-pads reach to a))out the sixth 

 segment. 



Life histori/.— "The life cycle of Thr/^?s tritici is quite short, reijuir- 

 ino- but twelve da3^s. Eggs are deposited in the tissues of infested 

 plants, and hatch in three days. The larval state lasts for about five 

 days durino- which time the insect makes two molts, the second when 

 errtering the nymph stage. The nymph stage continues for about 

 four days, during which time they take no food, rarely move to any 

 extent, but remain hidden away.'' 



Ecoiwmic considerations. — This is one of the most widely spread 

 and generally injurious species in this country. The specimens from 

 which Fitch described the species were taken at Geneva, Wisconsin, 

 from a wheat field which was being injured by the little pests. At 

 various times it has been noticed swarming in the blossoms of orange 

 and (;ausing injury thereto. It is a very common species on a large 

 number of flowering plants, both wild and cultivated, but unless pres- 

 ent in great numbers their injuries are likely to pass unnoticed. By 

 far the greatest damage appears to be done to strawberries, in the 

 blossoms of which they swarm, and by theii- punctures of the essential 

 parts of the flower they prevent its fertilization and the consequent 

 development of the fruit. This failure of l^loom, though perhaps pro- 

 duced at times by other insects and in other ways, is known to grow- 

 ers as "buttoning." The most serious injuries have been reported 

 from Florida and Illinois. In Florida' the strawberry crop in some 

 sections has been reduced to one-third in <lrv seasons. 



EUTHRIPS OCCIDENTALIS Pergande. 



Tfirips sp. CoQuiLLETT, Ins. Life, IV, 1891, x). 79. 



Euthrips occidental^ Pergandk, Ins. Life, VII, 1S9.^, |). 392. 



Female. — Length about 1 ram.; width at mesothorax about one- 

 fourth the body length. General color head pale lemon yellow, 

 thorax orange A^ellow, abdomen ])rownish yellow. 



Head about one and one-third times as broad as long, three-fourths 

 as long as the prothorax and considerably withdrawn into the latter. 

 Eyes rather large, occupying together about three-fifths the width of 

 the head, dark, slightly pilose; ocelli subapproximate, pale yellowish, 

 margined with reddish orange crescents; one very prominent spine 

 between ocelli on each side; post-ocular spines very conspicuous. 

 Maxillary palpi three segmented. Antenme about two and one-half 

 times as long as the head; first segment slightly shorter than the style; 

 two is one and one-half times as long as one; three is longest; four is 

 six-sevenths as long as three; five is five-sixths as long as four; six 

 nearly as long as three; seven very short, about one-fourth as long as 

 five: eight is one and three-fifths times as long as seven. Color of one* 

 translucent whitish; two brownish yellow (uniform), basal parts of 



