J. D. Hood.
A New Eurythrips (Thysanoptera) from Trinidad.
Psyche 41(1):1-5, 1934.

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PSYCHE
VOL. XLI MARCH 1934 No. 1
A NEW EURYTHRIPS (THYSANOPTERA) FROM
TRINIDAD
University of Rochester, Rochester, N. Y. Through the kindness of Dr. C. P. Alexander, it has been possible to study a paratype of Eurythrips ampliventralis Hinds from the collection of the Massachusetts State Col- lege. This has resulted in the differentiation of the new species described below.
Eurythrips amplus sp. nov.
Female (macropterous) .-Length about 1.5 mm. (dis- tended, 1.9 mm.) Color brown, darkest in vertex and along sides of head and pterothorax and in distal portion of abdo- men, paler in abdominal segments I-IV, in proximal angles of V-VII, in proximal fourth and distal two-fifths of tube, and in legs (particularly at ends of tibiee and in tarsi, these being yellow) ; antennae dark brown, with base of segment I, apex and middle portion of 11, and pedicel of I11 nearly or quite yellow, IV-VII darkest basally, I11 paler apically; wings of fore pair pale brownish and darker at base; ocellar pigmentation red.
Head (PI. 1, fig. 3) fully 1.42 times as long as greatest width, which is at proximal third of cheeks, the latter nearly evenly but decidedly rounded to eyes and very slightly con- verging in basal third, with a somewhat wider and indis- tinct basal collar, serrate as seen from above because of



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2 Psyche [March
short anastornosing lines which do not extend onto dorsum of head excepting faintly at extreme base1, and with a slight tooth behind eyes; head sharply constricted at pos- terior margin of eyes, at this point narrowest and about 0.8 the least subbasal width, the width across eyes nearly equal to greatest width; vertex slightly elevated, subconical, dis- tinctly produced and overhanging, bearing the anterior ocellus at its extremity, distinctly subreticulate, and with two pairs of small setse, one of them behind the posterior ocelli, the other on sides of vertex and very ,slightly in advance of front margin of posterior oeelli; cheeks with about four pairs of similar small setae in addition to a pair behind and between postocular setae ; postoculars nearly clear, expanded at tip, 83u long and 90u apart. Eyes strongly protruding, composed of relatively few large con- vex facets, about 0.3 as long as head, their width greater than 0.9 their interval and about three-fourths their length. Ocelli present, the posterior ones about 17u in diameter and about 0.6 as wide as their interval, the median ocellus with posterior margin far (12%) in advance of anterior margin of eyes. Antennae (PI. 1, fig. 4) about 2.16 times as long as head, segments VI-VIII rather compactly united because of the very short and broad pedicels of VII and VIII, which are retracted into the apices of the preceding segments, VII with pedicel about l5u wide and very nearly twice as broad as that of VI, VIII with pedicel Bu wide; sense-cones slender, the number on inner (and outer) surface of seg- ments as follows : I11 1 (2) , IV 1 (2), V I (l+l) , VI 1 (PI), VII with the usual one on dorsurn near apex; setae long, slender, pale and pointed. Mouth-cone broadly rounded at tip, supasssing middle of prosternurn.
Prothorax (PI. 1, fig. 3) along median line of pronotum about two-thirds as long as head and (inclusive of coxse) about twice as wide as long, with a short vestigial median thickening, with a few faint lines of sculpture along poste- rior margin, and fused with posterior half of epimera; anterior marginal setae minute, the others nearly colorless, IIn order to show these at all in the figure, it has been necessary to represent them more conspicuously than they show in the specimen.



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19341 A New Eurythrips from Trinidad 3
long, and dilated at tip, the anterior laterals 80u, midlaterals '781-1, epimerals 79u, posterior marginals 87u, coxals 50u. Pterothorax distinctly wider than prothorax, notal plates nearly smooth. Legs normal; fore tarsus with a slight downwardly-directed tooth or claw at inner distal angle of first segment. Wings normal, the fore pair (PI. 1, fig. 2) without accessory setse and with the three subbasal setse long, knobbed, pale, and comparable with those on anterior angles of pronotum.
Abdomen about 1.4 times as wide as prothorax across coxae, free of sculpture save for the usual dark transverse line near bases of terga 11-IX, major setse mostly knobbed, the lateral pair on VII about 113u and pointed, its homo- logue on VIII about 97u and knobbed, that on IX about 12311 and nearly pointed; tube (PI. 1, fig. 1) about two-thirds as long as head and only 1.57 times as long as greatest sub- basal width, this twice the apical width, sides very slightly concave in distal five-sixths, its terminal setae pale and nearly 0.9 its length.
Measurements of holotype ( ) : Length about 1.51 mm. (distended, 1.89 mm.) ; head, length 0.205 mm., greatest width (at basal fourth) 0.144 mm., width across eyes 0.139 mm., width at posterior margin of eyes 0.111 mm., least subbasal width 0.140 mm.; eyes, length 0.060 mm., width 0.045 mm., interval 0.048 mm. ; prothorax, median length of pronotum 0.137 mm., width (inclusive of coxse) 0.277 mm. ; pterothorax, greatest width 0.331 mm. ; abdomen, greatest width (at segment IV) 0.388 mm. ; tube, length 0.132 mrn., width near base 0.084 mm., at apex 0.041 mm. Antenna1 segments: 1 2 3
4
5 6
7 8
Length (u) :
50 53 70
66
60 59
49 37
Width (u) : 42
32
30
29 27
26 22 13
Total length of antenna 0.444 mm.
Described from one female taken by Dr. C. B. Williams at St. Joseph, Trinidad, March 4, 1918, by sweeping grass. It is in some ways difficult to compare this with the closely allied E. ampliventrails Hinds, because one is known only in the macropterous form, the other only in the



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4
Psyche, 1934
Psyche
[ March
VOL. 41, PLATE I
Hood-Eurythrips




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19341 A New Eurythrips from Trinidad 5
brachypterous.
One important difference, not correlated with wing development, is the peculiar structure of the pedicels of the last two antenna1 segments. In mplm these are very short, widened basally, and that of the pe- nultimate segment is nearly twice as wide as that of the sixth. Other differences lie in the much larger size of amplus, in the longer and proportionately slenderer anten- nal segments, and in the much stouter tube. In ampli- ventralis this last is about 143 microns long and 79 microns wide near base, and the proportion of length to breadth is thus 1.81, as against 1.57 in amplus.
EXPLANATION OF PLATE 1.
(Drawn by Miss Helen E. Rearwin; camera lucida.) Eurythrips ampins sp. nov.
Fig. 1.-Abdominal segments VIII-X,
Q , holotype.
Fig. 2.-Right fore wing, Q , holotype.
Fig. 3.-Head and prothorax, 9 , holotype ; all setae omitted from appendages.
Fig. 4.-Right antenna, $ , holotype.




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