20 NORTH AMERICAN THYSANOPTERA. 



(37) Phlceothrips Haliday. 



1. Postocular spines long and conspicuous. 



a. General color dark brown, with tibiae and tarsi bright yellow; cheeks nearly 

 straight; antennae one and three-fourths times as long as head. 



(100) Phl(xothnps uzeli Hinds. 



a\ General color yellowish brown, with considerable irregular red hypodermal 



pigmentation ; legs grayish brown ; cheeks slightly arched ; antennae 



twice as long as head (101) Phlceothrips pergandei Hinds. 



a'^^. General color brown; fore tibiae and all tarsi light brown; cheeks strongly 

 arched ; antennae one and one-half times as long as head . 



(102) Phlceothrips raptor Crawford. 



2. Postocular spines wanting; general color dark mahogany brown, with many smaller 



white pigment markings along head, thorax, and abdomen, and on 

 legs (103) Phlozothrips maculatus Hood. 



(38) Genus Liothrips Uzel. 



1. Head about one and three-tenths or less times as long as wide. 



a. Fore wings brownish at extreme base; head about one and fifteen one-hundred ths 

 times as long as wide; marginal abdominal bristles yellowish; tube 

 eight-tenths as long as head (104) Liothrips ocellatus Hood. 



a'. Fore wings nearly black in basal half; head about one and three-tenths times 

 as long as wide; marginal abdominal spines nearly black; tube 

 six-tenths as long as head (105) Liothrips umbripennis Hood. 



a^^. Fore wings brownish in basal half. 



(106) Liothrips umbripennis mexicanus Crawford. 



2. Head about one and five-tenths times as long as wide. 



a. Antennae lemon-yellow; spines on prothorax large and prominent; mid laterals 

 present, fully as long as anterior marginals; tube two-thirds as long 



as head (107) Liothrips citricornis Hood. 



a'. Antennal segments 1 and 2 concolorous with head; spines on prothorax not 

 prominent; mid laterals wanting. 

 b. Antennae with segments 1 and 2 almost black, 3 light yellow to light brown, 

 others brown; tube one-half as long as head. 



c. Head converging anteriorly (108) Liothrips fasciculatits Crawford. 



(/. Head distinctly converging posteriorly. 



(109) Liothrips fasciculata stenoceps Crawford. 

 V. Antennae one and two-thirds times as long as head; segments 1 and 2 dark 

 brown, concolorous with body, others yellow. 



(110) Liothrips balceri Crawford. 



h'\ Antennae one and one-fourth times as long as head; segment 1 and base of 



2 concolorous with body, apical half of 2 and of 5 and 6 to 8 light 



brown; 3, 4, and basal half of 5 yellow; tube one-half as long as 



head (Ill) Liothrips incconnelli Crawford. 



(39) Genus Idolothrips Haliday. 



1. Wings wanting or reduced to pads; all tibiae and tarsi bright yellow; tibiae often 



clouded with brown at base (112) Idolothrips flavipes Hood. 



2. Wings fully developed but short. 



a. Average length 5.28 mm.; color deep black; entire body sm-face, including 

 femora and tibiae, finely reticulated; tarsi yellow. 



(113) Idolothrips angusticeps Crawford, 

 length about 4 mm.; color coal-black, without markings; tarsi dark 

 brown (114) Idolothrips coniferarum Pergande. 



