THR HESSIAN FLY IN GREAT BRITAIN. 171 



being partly covered with black scales, which are more numerous 

 on the second than on the first and third divisions, and entirely 

 cover the terminal joint. Proboscis very small, and of a pink 

 colour. Antennae rather more than a third of the length of the 

 body, yellowish brown, consisting of seventeen joints shortly 

 verticillated with black hairs. The two basal joints are nearly 

 twice as thick as the others ; the first is club- or rather cup- 

 shaped ; the second nearly globular ; the next are all smooth and 

 cylindrical (turning irregular in size and shape when dry), about 

 twice as long as broad, becoming gradually rather smaller towards 

 the end, and terminating in an elongated tapering joint, which is 

 about half as long again as the one before it. Collar or neck 

 pinkish yellow. 



Thorax black, with grey reflections, having a few scattered white 

 hairs on the sides, and two indistinct lines of thinly placed white 

 hairs along the dorso-central region.* A pinkish red irregular- 

 shaped streak or patch run? from the side of the neck along the 

 lower side of the thorax to the base of the wing. Scutellum 

 black, prominent, and crested with black hairs. Halteres pale 

 red, irregularly clothed with patches of black scales. 



Abdomen pinkish or yellowish brown, with eight segments ; 

 the first is nearl}^ black; all the others are marked on each side 

 of the dorsum with a large square velvet-black spot, which spots 

 are separated by a considerable longitudinal space from those on 

 the opposite side on all the intermediate segments, but become 

 nearly confluent on the seventh and eighth joints.! A single row 

 of similar large square spots runs down the centre of the ventral 

 surface. The oviduct consists of three joints ; the basal one is 

 thick and rounded, the second and third are cylindrical, the last 

 one being of about half the diameter of the second, pointed, and 

 without lamellse. They are all pale red, the terminal one being 

 brown at the tip. 



Legs pink, becoming brownish yellow after death, clothed 

 irregularly with black scale-like hairs, which are generally thicker 

 in the neighbourhood of the joints. The coxae are brown, the 

 short fore femora or trochanters black, the others yellowish brown, 



* See Osten-Sacken's Essay on Comparative Chsetotaxy. 



+ Miss Ormerod, in her excellent paper upon the Hessian Fly, has described a 

 small V-shaped mark on the back of the seventh and eighth segments. I was not 

 so fortunate as to see it in the specimen which I examined. 



