TWO NEW SPECIES OF IDOLOTHRIPS. 



By J. DoiGLAS Hood, Urbana, Illinois. 



Of the two species of Idolothrips to be described below, the 

 former has been known to me for more than two years, but only 

 recently have I recognized it as distinct from I. coniferarum 

 Pergande, which was described in 1896. I regret that I have 

 been unable directly to compare these species, but I have never 

 met with the latter in the field, and have been unable to secure 

 specimens from the original describer. 



The value of the antennal sense cones in the definition of 

 species seems to have been first recognized by Dr. Hinds, and in 

 his descriptions, their form, size, and position are usually noted. 

 In view of the value of these structures in specific, if not generic, 

 determination, I have ventured to introduce into the following 

 descriptions a method of lecording their positions. The number 

 of the antennal segment is followed, first by the number of sense 

 cones on its inner surface, and then by the number on its outer 

 surface; rudimentary cones are indicated by an exponent pre- 

 ceded by a plus sign. Thus 3, 2-1+^ means that on the inner 

 surface of the third antennal segment are situated two fully- 

 developed sense cones, while on the outer surface there is one 

 fully developed and one rudimentary, cone. 



Genus IDOLOTHRIPS Haliday, 1852. 



Idolothrips armatus sp. nov. (tig. 9; 1,2, and Sa). 



Female. — Length about 3.3 mm. Color black; antennal segments 3-5 yel- 

 low basally; tarsi blackish brown; fore tibise often brownish yellow along middle 

 of inner surface. 



Head about two and one-half (2.44-2.64) times as long as wide; narrowest just 

 behind eyes, widest just before the base, and without "neck-like constriction"; 

 dorsal and lateral surfaces finely striate, sparsely set with short, subequal, 

 inconspicuous spines; vertical bristles slightly shorter than the postocular, 

 which are about one and one-half times as long as eyes; vertex conical, produced, 

 apex overhanging insertion of antennae. Eyes large, prominent, bulging, finely 

 faceted, distance across them almost equal to greatest width of head. Ocelli 

 small; anterior ocellus occupying extreme vertex; posterior ocelli nearly opposite 

 centers of eyes and slightly removed from their inner margins. Antennae 

 slender, eight-segmented, about 1.4 times as long as head; seginents 3-5 clavate; 

 6 and 7 sub-cylindrical, pedicellate; 8 lanceolate; segments 1 and 2 nearly 

 concolorous with body, 2 slightly paler apically; segment 3 yellow, apical sixth 

 clouded with black; segments 4 and 5 with respectively their basal two-thirds 

 and two-fifths yellow; remainder of antenna concolorous with body; sense cones 

 long, slender, transparent, scarcely distinguishable from the antennal bristles; 

 formula; 3,0-1 ; 4, 1-2; 5, 1-1 +"' ; 6, 1-0+ ' ; 7 with one on dorsuin near apex, and 

 3 and 4 each with a sub-apical one on ventral surface. Mouth cone short, 

 broadly rounded, reaching about to middle of prosternum. 



28.=; 



