DURHAM DIPTERA. 197 



XXVIII. 399. 



were being actually enclosed within its 

 cocoon by the full-fed spinning-up of the 

 larva of the bee. 

 "On one occasion, in July, 1877, 1 took a dead 

 female of Volucella bombylans from a nest of 

 Bombus latreilellus, Kirb., var. distinguendus, 

 Mar. In this nest there were Volucella 

 larvae not full grown. I think it very 

 probable that this insect had paid the 

 penalty of death at the hands, or rather 

 stings, of its would-be hosts for its intrusion 

 into their home for the purpose of ovi- 

 position, and that the dipterous larvae 

 present were its offspring." 



e (d). Last abdominal segments reddish haired. 



(var. hczmorrhoidalis, var. b, Ztt.) 

 f (c). Pale haired all over. 



var. hczmorrhoidalis, var. a, Ztt. 

 Wearhead, 1 ?, 4-8-97. This variety mimics 

 Bombus agrorum. 



2(1). Body almost bare; scutellum with conspicuous black 

 marginal bristles. 



3 (4). Abdomen with yellow cross bands. (1565. inanis, L.) 



4 (3). Abdomen shining black, but with conspicuous pale 



markings on the second segment. 



5 (6). Abdomen with a pair of large orange spots on the 



second segment. Hairs on the thorax almost all 

 pale. (1566. inflata, F.) 



6 (5). Abdomen with the second segment nearly all whitish 



translucent. Hairs on the thorax all black. 



1567. Volucella fie Hue ens, L. 

 Fairly common everywhere. Acts as a scavenger in 



the nests of Vespa vulgaris, according to Dr. P. B. 



Mason. 

 Mr. Robson, of Birtley, writes me that he has seen 



one resting on the footboard of a weak hive of bees. 



