124 [June, 



wing, a transverse scries of wliitish spots, forming a broken zigzag fascia, com- 

 mencing with one of the former whitisli spots on the subcosta, and ending with that 

 on the axillar nervure, adrancing obliquely over the base of the radial fork and over 

 the cubitus, to its salient angle on the anterior pobrachial, opposite the end of the 

 axillar nervure, and having its re-entering angle on the postical nervure, opposite 

 the radial bifurcation, or interior to this in the male ; also a whitish spot on the 

 axillar nervure, nearly midway between the end of the fascia and the fold of 

 deflection. Over white paper, from certain positions, a portion of the base of the 

 wing also appears whitish, and the ground colour of the wing shifts from light 

 brownish-grey to light grey. When resting on a wall, in the evening, the insect is 

 apt to appear blackish-grey. Fringes match with the prevailing tint of the wing, 

 but readily shift to a darker tint, or reflect a lighter dull satiny gloss. The dark 

 spots, above mentioned, at the margin are relatively small and rarely equal in size, 

 the three at the posterior margin being usually more distinct than those at the costa, 

 and the spot of the axillar often slightly larger and more strongly marked than 

 either of the other two ; that of the subcosta blending with some dark hair on the 

 anterior radius, appears to be the biggest of all, but lacks sharpness of definition, 

 and is often nebulous ; and when there are only six spots instead of seven, it is 

 usually the spot of the posterior radius which is missing. Tints of iridescence of 

 the wing-membrane chiefly red, green, and yellow. Hair of head, antennae, body, 

 and legs whitish, with the same changeable tints of grey and brown as the wings ; 

 the parts underlying the hair, light coloured in life, grow darker in drying. Antennae 

 (usually 14-jointed) reach in the <? only to the base of the wing. Joints of palpi 

 enumerated in the order of lessening length, 4, 2, 3, 1. Basal joint in the superior 

 S appendages short and moderately stout ; apical joint longer, and, when dried, 

 narrowly and acutely falcate, with a slight median dilatation. Inferior ^ appendages 

 similar to those of the preceding species ; the limb in profile subulate-acuminate ; 

 hair dense and long ; tenaculum short and slender. 



Common in England in the resorts of Trichomyia urhica and pig- 

 sties during summer and autumn, and also at cattle-drinking places. 

 In Algeria, abundant in all French towns, and by streams in their 

 neighbourhood, not excepting Biskra, on the border of the Sahara ; 

 found frequently on board passenger steamers in the harbours, flying 

 in at the port-holes. The possibility of its following commerce to 

 different parts of the world is obvious, and may account for its 

 occurrence in N. Americ-a, if the species described by Say, cited above, 

 be the same as the European insect. Unless disproved on comparison 

 of specimens from both these continents, their specific identity may 

 be assumed on the authority of Banks's descinption. 



1. PsTCHODA LuciFUGA (Hal., MS.), Walker. 



Pericoma Incifuga, [Hal., MS ], Walker, Ins. Brit. Dipt., iii, 257 (1856).— Ps^- 

 choda lucifuga, Verrall, List Brit. Dipt., p. 10 (18S8) ; Etn., ante, 2nd ser., vol. iv, 

 129, step 2, and vol. v, pi. iv, Ps. 1 (detail). 



Reseu.blee Fs. phalcenoides (2) in the colour of the wings, but may be dis- 



