476 TROMOPTERA 



" of masonry by which the grubs of the Mason-bee, Chalcidroma murcma, 

 " are protected. From this egg there is hatched a minute delicate vermi- 

 " form larva. In order to obtain its food, it is necessary for this feeble 

 " creature to penetrate the masonry ; apparently a hopeless task, the 

 " animal being scarcely a twentieth of an inch long and very slender . . . 

 " the frail creature hunts about the surface of the masonry, seeking to 

 " find an entrance ; frequently it is a long time before it is successful ; 

 " but though it has never taken any food it is possessed of great powers of 

 " endurance. . . . Finally, after greater or less delay, the persevering little 

 " larva succeeds in finding some tiny gap in the masonry through which 

 " it can force itself. . . . Having once effected an entrance the organisation 

 " that has enabled it to do so is useless ; this primary form of the larva," 

 which may have lived without food for some weeks, " has, in fact, as its 

 " sole object to enable the creature to penetrate to its food. Having 

 " penetrated, it undergoes a complete change of form, and appears as a 

 " creature specially fitted for feeding on the quiescent larva of the bee 

 " without destroying it. To accomplish this requires an extreme delicacy 

 " of organisation and instinct; to bite the prey would be to kill it, and if 

 " this were done, the Anthrax would, Fabre supposes, ensure its own 

 " death, for it cannot feed on the dead and putrefying grub ; accordingly, 

 " the part of its body that does duty as a mouth is merely a delicate 

 " sucker which it applies to the skin of the Ghalcifloma-gv\xh\ and thus 

 " without inflicting any perceptible wound it sucks day after day, changing 

 " its position frequently, until it has completely emptied the pupa of 

 " its contents, nothing being left but the skin." The larva changes to a 

 pupa the next spring, and then is provided with a special apj)aratus for 

 piercing the enclosing masonry. "Thus this species appears in four 

 " consecutive forms — in addition to the egg — each of which is highly 

 " specialised for the purposes of existence in that stage," The males of 

 the genus Bomhylius are magnificent hoverers in bright sunshine, and are 

 capable of evading quick strokes of a net and then boldly renewing their 

 hovering in almost the same spot ; the females however usually hover in 

 a more feeble fashion at blossoms or low growing plants in somewhat the 

 same fashion as the Humming-bird moth {Macroglossa); the species of 

 Anthracince commonly rest on bare hot sand or on bare patches, or foot- 

 paths on heaths and commons, though even then they are very ready to 

 move with a peculiar hovering flight, and the females may be found on 

 the blossoms of large UvibcUifcrce. 



The Boinhylidce form a large family of very beautiful flies, of which 

 many show most varied forms of wing coloration while others show most 

 attractive hues in the pubescence or scales ; sometimes bright silvery tufts 

 appear at the wing-base or near the end of the abdomen, or cross-bars 

 or small spots occur on the abdomen, and in some exotic species 

 brilliant prismatic scales occur on the frons and scutellum ; many of 

 these varied hues can only be seen in certain lights, and a specimen which 



