226 IOWA ACADEMY OF SCIENCES. 



at sides and toward apex; narrow basal band on segments 2-7, expanding 

 laterally and broken up into spots, one of which ie more conspicuous 

 than the others, brown. 



Femora and tibiee dusky or brownish on upper surface, pale on lower 

 surface and at base, the latter also pale at tip; anterior wings dusky yel- 

 lowish; spines brown. 



By its seven-jointed antennae. T. lactiiae is allied to T. tahaci, Lind., 

 but it is more heavily marked with brown; the color of the intermediate 

 joints of the antennas is darker: the antennas and the ocelli more approx- 

 imate; the ocelli more conspicuous and farther removed from the anterior 

 margin of the vertex; the prothoracic bristles larger and less uniformly 

 distributed, being entirely absent from two discal areas; those at 

 posterior angles, longer; proximal spines on cubitus arranged in a single 

 group. 



Described from numerous specimens taken on wild lettuce 

 in October, November and March, at Ames, Iowa. 



T. lactucce bears some resemblance to T.. triticl in size and 

 general color, from which it may be easily separated by the 

 fewer antennal joints, less rectangular head, less widely sep- 

 arated ocelli, absence of long bristles at anterior angles of 

 prothorax, less numerous cubital spines and their arrangement 

 in groups, absence of spines at apex of intermediate and 

 anterior tibias and inner margin of posterior tibiae. 



From T. striata it may be known by the diiference in number 

 of antennal joints, absence of annulation on sixth joint, pres- 

 ence of longer and more numerous spines and bristles. 

 Thrips pallida n. sp. 



Female: Length 1.12 mm. Color varying from white to pale yellow. 

 Antennas, beyond basal joints, more or less dusky. Head small, eyes large. 

 Anterior wings partially trifasciate. Bristles on anterior portion of body 

 long and slender. Prothorax characterized by the presence of a long 

 bristle on the middle of each lateral margin in addition to those at anterior 

 and posterior angles. 



Head small, about as long as broad Occiput very short, not more than 

 one-third the length of the head. Eyes dark red-brown, very large and 

 prominent, sparsely and feebly pilose. Vertex narrow, elevated, trans- 

 versely convex, ascending toward the anterior margin, the latter arcuate. 

 Ocelli in middle of vertex, nearly colorless, their inner margins white, con- 

 tiguous anteriorly. Ocellar bristles as long as the head. Front prominent, 

 bearing a row of recurved bristles above insertion of antennas. Mouth 

 parts short, nearly symmetrical. 



Antennae approximate; the two basal joints the stoutest; joint 1 semi- 

 globose, one-half the length of joint 2; the latter is stouter than the former, 

 barrel-shaped, equal in length to joint 5, and a little shorter than joints 3 

 or 4: these are robust, subequal in length and broadly obovate, the pedi- 

 cel of joint 3 is short and slender; joint 5 is oval and less robust than the 

 two immediately preceding; the remaining joints are sessile, together form 



