Mesothrips guamensis, Moulton, 1942

Moulton, Dudley, 1942, Thysanoptera: Thrips of Guam, Insects of Guam I, Bernice P. Bishop Museum Bulletin, pp. 7-16 : 13-14

18. Mesothrips guamensis , new species.

Male holotype: blackish brown, only joints of legs and fore tarsi lighter; wings brownish.

Head 1.8 times longer than wide, sub-rectangular in shape, cheeks straight, slightly narrowed posteriorly and with a basal thickening; eyes broadly rounded, not protruding; cheeks with several scattered small spines; postoculars longer. than eyes, pointed. Mouth cone reaching two thirds across prosternum, narrowed near the middle and from there more or less pointed to tip. Antenna! segments 3 to 5 broadly clavate, 6 and 7 subovate but narrowed at base, 8 broadly spindle shaped. Segment 3 with two sense cones, 4 with five sense cones. Anterior margin of prothorax deeply concave, with a median thickening extending from lower line of crescent to a strong transverse line in front of posterior margin, forming an inverted T. All normal spines present, the outer pair at posterior angles longest, inner pair somewhat shorter, midlaterals still shorter and those on anterior margin and angles much smaller. Fore legs greatly enlarged, each fore tarsus armed with a broad-seated tooth. Wings long, slightly narrowed in the middle, each forewing with 34 double fringe hairs. Spines on posterior angles of abdominal segments 5, 6, 7 and 9 very long. Tube approximately 0.8 as long as head and 3.5 times longer than width at base.

Total body length 3.5 mm.; head length 0.47 mm., width across eyes 0.264 mm.; near posterior margin 0.22 mm. Prothorax length measured from a transverse line connecting anterior angles 0.308 111111.,and 0.235 111111.when measured from the lower middle point of the anterior margin crescent; tube length 0.367 mm., width at base 0.102 mm. Antenna! segments length (width): I, 50 (50); II, 76 (40); III, 113 (46); IV, 116 (SO); V, 106 (43); VI, 66 microns. Segments 7 and 8 are not in position to be measured accurately.

Length of spines: postoculars 150; those on anterior margin and angles subequal, 66; midlaterals 83; on posterior angles outer 133, inner 100; on ninth abdominal segment 367, at tip of tube 294 microns. Length of fore femora 0.455 mm., width near middle 0.176 mm.

Upi, May 5, under bark of Hibiscus tiliaceus along with Mesothrips swezeyi , holotype male, Swezey ( 5465 ).

This species, although having the same general appearance and color as swezeyi is easily separated by the crescent-shaped fore margin of prothorax.

From jordani it may be separated by its uniformly dark brown antenna; from setidens by its broadly triangular tarsal tooth without setae; and from alluaudi Vuillet which has a clear yellow third antennal segment (in guamensis the antenna is uniformly dark brown).