BY H. H. KARNT. 271 



men longer than the segments themselves. Fore-femora somewhat more than 

 half as wide as long. Pterothorax comparatively shorter and wider than in the 

 maeropterous form. Wings absent. Wing retaining spines reduced to simple 

 bristles. 



Measurements of an apterous female of middle size: Total length of an- 

 tennae, 0.35 mm.; joint 1, 0.04 mm. long, 0.05 mm. wide; joint 2, 0.055 mm. long, 

 0.045 mm. wide; joint 3, 0.055 mm. long, 0.04 mm. wide; joint 4, 0.045 mm. long, 

 0.04 mm. wide; joint 5, 0.04 mm. long, 0.04 mm. wide; joint 6, 0.04 mm. long, 

 0.035 mm. wide; joint 7, 0.04 mm. long, 0.03 mm. wide; joint 8, 0.03 mm. long, 

 0.015 mm. wide. Head 0.28 mm. long, 0.22 mm. wide. Prothorax 0.35 mm. long, 

 0.50 mm. wide without fore-coxae, 0.68 mm. wide including fore-coxae. Fore- 

 femora 0.48 mm. long, 0.26 mm. wide; fore-tibiae (including tarsi) 0.24 mm. long, 

 0.08 mm. wide. Pterothorax 0.42 mm. long, 0.56 mm. wide. Middle femora 

 0.18 mm. long, 0.07 mm. wide; middle tibiae (including tarsi) 0.21 mm. long, 

 0.05 mm. wide. Hind-femora 0.21 mm. long, 0.09 mm. wide; hind-tibiae (in- 

 eluding tarsi) 0.28 mm. long, 0.06 mm. wide. Abdomen (including tube) 1.8 

 mm. long, 0.55 mm. wide. Leng-th of tube 0.17 mm., width at base 0.10 mm., at 

 apex 0.04 mm. 



Forma macroptera. Head distinctly longer, at least one and a half times 

 as long as wide. Eyes occupying a little more than one-fourth of the length of 

 head. Ocelli also larger than in the apterous form. Antennae distinctly longer, 

 their middle joints at least one and a half times as long as wide. All bristles 

 long and stout, but shorter than in the apterous form, distinctly dilated at apex, 

 knobbed ; only those of the ninth abdominal segment and of tube sharply pointed. 

 The inner bristle of first antennal joint not considerably overreaching the end 

 of this segment. Fore-femora somewhat less than half as wide as long. Wing-s 

 present, reaching about to base of sixth abdominal segment, not constricted in 

 the middle, nor dilated before the apex, clear, hyaline, with long, dense fringe. 

 Fore pair with three long, knobbed, equidistant bristles near the fore-margin at 

 base, a little longer than the wing is broad; hind-margin near apex with a dozen 

 duplicated cilia. Wing retaining spines weak, but distinctly S-shaped, inwardly 

 directed. 



Besides the maeropterous and apterous forms, there are larger and smaller 

 ones. 



Forma major. Larger. Fore-femora somewhat larger, more than one and a 

 Half times as long as head. 



Measurements of a large maeropterous female : Total length of antennae 

 0.49 mm.; joint 1, 0.04 mm. long, 0.05 mm. wide; joint 2. 0.06 mm. long, 0.05 

 mm. wide; joint 3, 0.08 mm. long, 0.045 mm. wide; joint 4, 0.08 mm. long, 0.05 

 mm. wide; joint 5, 0.075 mm. long, 0.04 mm. wide; joint 6, 0.07 mm. long, 

 0.035 mm. wide; joint 7, 0.06 mm. long, 0.025 mm. wide; joint 8, 0.03 mm. long, 

 0.015 mm. wide. Head 0.38 mm. long, 0.24 mm. wide. Prothorax 0.40 mm. 

 long, 0.51 mm. wide without fore-coxae, 0.68 wide including fore-coxae. Fore- 

 femora 0.58 mm. long, 0.26 mm. wide; fore-tibiae (including tarsi) 0.32 mm. 

 long, 0.08 mm. wide. Pterothorax 0.55 mm. long, 0.61 mm. wide. Middle femora 

 0.17 mm. long, 0.07 mm. wide; middle tibiae (including tarsi) 0.25 mm. long, 

 0.055 mm. wide. Hind-femora 0.26 mm. long, 0.09 mm. wide; hind-tibiae (in- 

 cluding tarsi) 0.31 mm. long, 0.06 mm. wide. Length of wings (without fringe) 

 1.4 mm. Abdomen (including tube) 2.3 mm. long, 0.53 mm. wide. Length of 

 tube 0.21 mm., width at base 0.11 mm., at apex 0.04 mm. 



Forma debilis. Smaller. Fore-femora less than one and a half times as 



