THE AMERICAN ENTOMOLOGIST. 



281 



[Fig. 148 



In 1858 the real history of the Bombylius was 

 discovered by the veteran Leon Dufour, who, in 

 the spring, found various exuvire of the pupa of 

 B. uiajor sticking out of the ground, together 

 with the newly-hatched insect, in places much 

 frequented by various AndrenidiC, especially 

 ColUtcs hirta, and who succeeded in the autumn, 

 by digging on the spot, to find the larva " au 

 milieu des deblais, 011 gisaient par-ci par-la des 

 coques de Colletes" (Ann. Soc. Ent. France, 

 3rd ser., tom. vi., p. 505, pi. 13, fig. iii, and 

 details). The larva is elongated, apod and fleshy, 

 and of a white color. The preceding observa- 

 tions clearly prove that the larv:c of the Bombylii 

 are parasites in the nests of other insects, in the 

 manner of the cuckoo among birds. * * * 



This last statement of Prof. Westwood 

 is, however, not justified by Dufour's ob- 

 servations. On the contrary, Dufour ex- 

 pressly states that he did not observe upon 

 what the larva fed ; the inference which 

 he draws is based upon the analogy of 

 Anthrax *2iVLA. he inferred that it was upon 

 the larvae of Colletes that the grub fed — 

 quite a different thing from 

 being a cuckoo in the nest 

 and feeding only upon the 

 pollen. There is in Du- 

 four's paper no evidence to 

 prove that the Bombylius 

 larva was found in the co- 

 coons, or even in the cells, 

 of the bee; he states, in fact, 

 that he failed to find it there, 

 but found it amid the clear- 

 ings {deblais) which he had 

 made in digging out the 

 nest. Prof. Westwood himself found num- 

 bers of Bombylius medius flying in asso- 

 ciation with a species of Andrena in the 

 unpaved Forum Triangulare of Pompeii, 

 and also at the same spot the pupal exuvi- 

 um of the fly protruding from the ground, 

 which is presumptive evidence of the 

 correctness of his conclusion. 



Dr. Packard ("(iuide," etc., p. 397) 

 states that "a species [of Bombylius^ is 

 known in England to lay its eggs at the 

 opening of the holes of Andrena, whose 

 larvje and pupae are devoured by the larv^ 

 of the fly." But no authority is given for 

 the statement. 



SVSTIKCHUS OREAS: 



pupa (after Riley) 



Messrs. Allen and Underbill in Science 



Gossip, 1875, p. 80, express their belief that 



the Bombylii are parasitic on humble-bees. 



In the volume for T876, p. 171, they say 



(speaking of Sitaris) : 



In relation to the larva of this beetle, we would 

 remark that this year we have found it clinging 

 to Bombylii. This is "circumstantial evidence" 

 that Bombylii frequent the nests of Anthophora 

 to lay their eggs, since Silaris itself, from its 

 manner of life, cannot be the parasite of a fly, 

 but only of a bee. 



Locust eggs might well have been in the 

 spots where Lucas, Dufour and Westwood 

 found Bombylius. 



From all these notes, it is clear that the 

 true habit of Bombyliid larvae had not 

 been clearly ascertained. That they preyed 

 parasitically on nest-building Hymenoptera 



[Fig. 149.] 



*lt has been clearly ascertained, and is well known, that 

 J «Mrrt^ feeds in the larva state upon the young of certain 

 bees. The larva of the Anthrax before attaining its full 

 growth and before destroying its host must await the full 

 growth of the latter, as it has by several observers been bred 

 from the cocoons of the insect upon which it was parasitic. 



SvsTciiCHUS OREAS : female; antenna, suli. w 

 top view, to right. 



was rendered probable by what was 

 known of the parasitism of the allied An- 

 thracids ; but we had only assumption 

 without proof, and the experience we now 

 record weakens the force of the assumption. 

 In his " Western Diptera " (/. c, p. 243,) 

 Baron Osten Sacken gives references to 

 the published account of the parasitism of 

 the Anthracid genus Argyranmba within 

 the nests of Cemo?ius and Chalicodoma ; 

 cites Schiner's statement that the larvae 

 live parasitically in pupse of Lepidoptera, 

 and records the breeding of A. cephus and 

 A. fur from the nest of a Texan mud- 

 wasp which he referred, with a question, to 

 Pelopceus, but which, as we have ascertained 

 from an examination of the mud tubes 

 which are deposited in the Cambridge 

 Museum of Comparative Zoology, belong 



