A. A. GIRAULT. 53 



Female. — Length, 0.65 mm. Visible to unaided eye; moderate in 

 size. 



Similar to Pentarthron mhncfum (Riley) and P. semblidis 

 (Aurivillius) in aspect and structure but differing in habitus 

 and as follows : 



Mainly in ciliation of the wings. The oblique line of discal cilia 

 running back from the knob of the stigmal vein has at the most three 

 cilia, usually two, hence is short ; the discal ciliation is denser, less 

 distinctly arranged in straight lines ; the marginal ciliation of the fore 

 wing is distinctly longer. In the posterior wings the two caudal lines 

 of discal cilia are complete ; the anterior line of cilia is distinctly more 

 than half complete, containing from seven to eight cilia (in niinutum 

 and semblidis, this anterior line is short usually containing from two 

 to six cilia and not more than half complete, usually not half com- 

 plete ; the posterior line is incomplete). 



Differing next in antennal structure : The funicle joints are both 

 distinctly wider than long, transverse, the first longer than the second 

 but neither longer than wide or subquadrate. Otherwise, the same 

 structurally as the two other species mentioned. Easily separated 

 upon comparison of specimens and with the characters given but not 

 without care in either case. 



In color differing from normal yellow specimens of niinutum in not 

 being intensely yellow but grayish or dusky yellowish, dull in color, 

 the abdomen varying to brown-black ; doubtless, as in nmiulum the 

 general body coloration is widely variable.* The fore wings are fu- 

 mated proximad as in ininutum, but not conspicuously as is usual in 

 semifumatum Perkins. Antennae normal — scape, pedicel, ring-joint, 

 two funicle joints and a solid club, shorter than in minutum. 



From 7 specimens, s-inch objective, 1-inch optic, Bausch 

 and Lomb. 



Male.^ — Decidedly smaller, minute, mere specks to the unaided eye. 

 Length variable, averaging 0.20 mm. Wingless, the tarsal joints short- 

 ened. Antennae short, the scape, pedicel and ring-joint distinct, normal, 

 the funicle and club united into a conic-ovate club as long as the scape 

 but distinctly divided into funicle and club regions but the two funicle 

 joints united into a solid piece. Club with but moderately long hairs 

 as in the normal males of the genus. 



From 17 specimens, same objective and eye-piece ; also 

 high power. 



This species is similar to semblidis Aurivillius in having 



* See following. 



t See later for description of the winged male. 



TRANS. AM. KNT. SCO. , XXXVII. 



