tennae arise, and the latter has serrated posterior thighs and 

 very short antennae, and our pretty little group is readily di- 

 stinguished by the shape of the abdomen, the 2nd and 3rd 

 segments appearing as if a thread had been drawn tight round 

 them at their attachment. 



The following have been recorded as British species. 



1. bicolor Fab."^ — Coquehert Icon. tab. '2.6. f. 9. 



" Abdomen rufous ; base and apex greenish-black ; tip of 



scutellum white : 3 lines long." 



This and No. 2 are I believe in the British Museum. 



2. arcuatus Meig. v. 3. tab. 27./ 20. & 21. 



" Black, apex of scutellum white; abdomen with a testa- 

 ceous fascia and 3 curved interrupted white bands : 3 lines." 



3. sigillatus Curt. Brit. Ent. jpl. 593. S • 



I have taken a single specimen at Darent I believe. 



4. obscurus Meg.-— Meig. 3. 183. 12. 



Bluish-black, antennas fuscous, face yellow with a black 



stripe ; legs ferruginous, thighs black, the apex yellow as 



well as the base of the tibiae: 9,\ lines. 



Obs. Sometimes the inside of the antennae is slightly ferru- 

 ginous in the male, and my P. geriiadatiis is a female with the 

 base of the same colour. 



I have taken both sexes on Hampstead Heath the beginning 

 of July ; they were flying over the ground, and so close to the 

 surface, that it was difficult to catch them; I have also met 

 with specimens at Dover the middle of the same month, and at 

 Hume, in Hampshire, the end of August. 

 6. femoratus Meg.— Meig. 3. 184. 14. 



" Black; hypostoma black, shining, with white hairs; legs 



yellow, thighs black, apex yellow ; posterior tibiee with a 



fuscous ring above the apex : 1 ^ line." 



Recorded by Mr. Stephens as inhabiting the neighbourhood 

 of London. 



The Plant is Sotichus arvensis (Corn Sow-thistle). 



