164 APID.E. 



with silvery white puhescence ; the antennae filiform and longer 

 than the head; the thorax more pubescent than in the female, and 

 truncate behind ; the abdomen inflexed at the apex ; the segments 

 with white narrow fasciae ; the sixth segment with its apical mar- 

 gin entire, compressed in the middle, on each side of which is a deep 

 transverse fovea. B.M. 



Heriades truncorum is a very rare species in this country, but 

 less so on the continent : I have received it from Westphalia in some 

 numbers. Mr. Kirby received it from his friend Mr. Trimmer, who 

 took it near Brentford, where I have searched for it unsuccessfully. 

 Mr. Ingall found it near Dulwich, taking three or four specimens. 

 It must no doubt be looked for about old posts and rails in June. 

 It is a species I never met with. 



Genus 9. CHELOSTOMA. 



Apis (pt.), Linn. Syst. Nat, i. 954 (1766'*. 

 Hvlseus (pt.), Fabr. Syst. Piez. 319 (1804). 

 Anthophora (pt.), Fabr. lib. cit, 372 (1804). 

 Megachile (pt.), Latr. Hist, Nat. xiv. 51 (1805). 

 Clielostoma, Latr. Gen, Crust, et Ins. iv. 161 (1809). 

 Heriades (pt.), Zett. Ins. Lapp. 467 (1840). 

 Gyrodroma (pt.), Thorns. Hym. Scand. ii. 259 (1872). 



Head subquadrate, rather wider than the thorax ; ocelli in a tri- 

 angle ; antenna subclavat<% short, a little longer than the head, 

 slender and filiform in the male, with the intermediate joints den- 

 ticulate beneath ; labru m elongate, narrowed anteriorly, and trun- 

 cate at the apex ; mandibles bidentate, ciliated on their inner mar- 

 gin ; the labial palpi 4-jointed, the basal joint one third the length 

 of the second, the second joint attenuated at the apex, the third short 

 and placed in a line with the second ; the fourth clavate and arti- 

 culated to the side and near the apex of the third. Maxillary palpi 

 3-jointed, the joints short and subequal. Anterior wings with two 

 submarginal cells, the second receiving both the recurrent nervures. 

 Abdomen as long as the head and thorax, subclavate, and with a 

 dense pollen-brush beneath ; in the male the abdomen cylindrical, 

 incurved, the apex armed with two blunt teeth ; beneath, the second 

 segment produced into a large concave mucro, the fourth segment 

 being densely pilose. 



This genus and Heriades are very closely allied : both have 3- 

 jointed maxillary palpi, and 4-jointed labial ; but in Clielostoma three 

 joints of the labial palpi are articulated in a line, the fourth being 

 attached to the side of the third ; in Heriades only two are in aline, 

 the third and fourth being minute and attached to the second ; the 

 neuration of the wings is the same in both genera. 



Both the British species burrow in decaying posts and rails ; but, 

 like many species of burrowing-bees, they occasionally make use of 

 ready-formed burrows. $ot unfrequently Clielostoma jlorisomne 

 makes use of straws and reeds, their tubes being admirably adapted 



