93 



Last pair of legs with a well-marked triangular projection on the hind face of 

 1st basal joint, inner ramus uniarticulate and rather short, not extending nearly 

 to the end of the 1st joint of the outer ramus, terminal joint of the latter well 

 defined and of larger size than usual, inner apical spine rather elongated, reaching 

 as far as the tip of the claw-like projection of the preceding joint. Ovisac in 

 some cases rather large, sub-cordate, in other cases comparatively small, with only 

 a limited number of ova 



Male still more slender than female, with the lateral parts of last 

 pedigerous segment less expanded, though somewhat more prominent on right 

 side. Right anterior antenna with the middle section not much tumefied, ante- 

 penultimate joint of terminal section produced at the end anteriorly to a hook- 

 like process, in some cases very prominent, in other cases much reduced in 

 size. Last pair of legs comparatively very large, with the inner rami rather 

 dissimilar, that of right leg being much the larger and somewhat tumefied, almost 

 fusiform in shape, extending far beyond the middle of the distal joint of the outer 

 ramus, proximal joint of the latter produced at the end outside to a comparatively 

 short triangular projection, distal joint very large and broad, with the spine of 

 the outer edge occurring somewhat in front of the middle, apical claw considerably 

 curved in its distal part. Left leg extending scarcely as far as the penultimate 

 joint of the right, inner edge of 2nd basal joint angularly produced beyond the 

 middle, terminal joint with a comparatively small lamellar expansion inside the 

 base, and gradually tapering to a simple digitiform process, inside which there 

 is a small seta, standing out from the joint at a right angle, and terminating in 

 a brush of delicate diverging cilia. 



Colour. Body generally very pellucid and almost colourless, in some 

 cases, however, ornamented with a broad transverse band of a chocolate hue 

 across the anterior division. 



Length of adult female 1.40 mm., of ma'e 1.20 mm. 



Remarks. This form is easily recognizable from the 5 preceding species 

 by its slender form, but especially by the exceedingly elongated anterior antennse. 

 Moreover the shape of the lateral expansions of the last pedigerous segment in 

 the female, and the structure of the last pair of legs in both sexes is rather 

 characteristic. Two varieties of this species occur in Norway, the one with the 

 anterior antennaB quite extraordinarily prolonged, the other with these appen- 

 dages somewhat shorter, but otherwise exactly agreeing with the former, no 

 difference whatever being found in the structure of the last pair of legs in either 

 of the sexes. The form described by Lubbock as D. Westwoodi seems more 

 properly to be referable to the latter variety. 



