40 



white; labellae dark; setae minute, curved, black. Palpi short, smaller than one- 

 fourth of the length of the proboscis; vestiture black, with a few white scales inter- 

 mixed, seta? moderate, black. Antennae moderate, with the joints subequal, rugose, 

 pilose, blackish, the second joint a little longer w r ith a yellow base; tori subspheri- 

 cal, with a cup-shaped excavation, bright brown, shaded with blackish scales; the 

 inner half covered with flat, sordid-white scales. Clypeus rounded-triangular, pro- 

 minent, blackish brown, nude. Eyes at all events on the newly hatched individuals 

 (in May June) metallic green. Occiput rather broad, black, densely covered with 

 narrow curved coarse scales, nearly pure white in a broad median zone; brown 

 laterally and with a patch of flat, blackish ones on the sides; a series of black 

 bristles along the hind edge of the eyes and long, snow r -white bristles between them ; 

 on the occiput many erect, broad, and rather short white forked scales centrally, 

 a few black ones laterally. 



Prothoracic lobes narrowly elliptical, remote dorsally, clothed with narrow 

 coarse brown scales at tip, whitish ones below and with short, brown bristles. 

 Colour of mesonotum extremely variable ; four main varieties. 



1. Mesonotum black, densely clothed with coarse, narrow curved, dull-yellow- 

 ish scales, laterally golden-brown ones in a broad median stripe, horded by a 

 yellowish-white narrow stripe, running from anterior angles to near the root of w r ing; 

 scales pale in the region of antescutellar space. 



2. Mesonotum brown, either densely clothed with coarse, narrow curved, dull 

 white scales over the whole surface or with a bright brown and usually narrow 

 median stripe. 



3. Mesonotum covered with almost snow-white scales with an almost black, 

 narrow median line. 



4. Mesonotum covered with almost snow-w r hite scales, with an almost black, 

 broad median line and laterally with two other black lines much shorter, only half 

 as long as the median line. 



Bristles dark, brown or yellowish white. Scutellum trilobate, luteous, clothed 

 with coarse dull white scales, each lobe \vith a group of about twelve very pale 

 bristles. Postnotum elliptical, prominent, nude, brownish luteous. Pleurae and coxae 

 brownish, clothed with flat, white scales and pale bristles. 



Abdomen: Subcylindrical, flattened, posterior segments tapering. Also the co- 

 lour of the abdomen extremely variable. The main form as follows: dorsal vestiture 

 of flat, sordid-white scales with two large patches of black ones on each segment, 

 the patches becoming smaller posteriorly and may be absent on last segment; first 

 segment almost white with many long white hairs; venter clothed with sordid-white 

 scales, a very narrow median broken line of black ones or row of rather large, 

 black spots; cerci black; setae mostly pale. Two colour variations are especially 

 common: 1. the whole dorsum of abdomen snow-white, only with small black, 

 divergent lines near the borders, most developed on segments two to six. 2. the w r hole 

 dorsum black, only with small basal bands of white scales. 



