so 



HARDWICKE'S SCIENCE-GOSSIP. 



fulcra (/), separate the lobes ; while the other pair, 

 inserted halfway do wn the said lobes at t, bring 

 them together again. We cannot find out the exact 

 point from which these tendons arise, for they appear 

 to fade away gradually. Down the labium run, as 

 is usual in all diptera, two tracheae, each of which 

 is considerably branched. The capillary channels 

 (sometimes called " false tracheae ") which servo to 

 gather up honey, pollen, &o, are, in this genus, 

 limited to three on each lobe of the labium : this is 

 very few in comparison with some flies ; but their 



Fig. 46. Bombylius medius, 

 natural size. 



Fi: 



;. 4". Antennae of B. 

 major, X 12 (Ha. 



Fig 48 Wing of B. major. The names of the veins are :— 

 oo, costal; sc, sub-costal; m, mediastinal; r, radial ; 

 ru, cu, cubital ; sa, subapical ; em, externo-medial -, pr, 

 prae-brachial ; pn, post-brachial ; an, anal ; a, discoidal 

 areolet ; axl, axillary lobe ; al, the alula. 



large size compensates for their small number. The 

 maxillae (mx) and the lingua (0 present no speci- 

 ally interesting features, save that the latter is hol- 

 low, instead of being merely a flat blade, as it is in 

 most flies. The labial palpi, which are to be found 

 in the mouths of flies of some families, are absent 

 in the Bombylii, but the maxillary palpi (mp), which 

 are shown in the figure, are present in every dip- 

 terous insect. 



The antennae of Humble-bee Flies (see fig. 47) have 

 six joints. The first and second are covered jwith 

 long hairs ; the third joint is very long,— it is covered 

 with short hairs ; the little pits on the surface, 

 formerly supposed to be the seat of hearing, but 

 now more generally believed to be the organs of 

 smell, are small, but numerous. The last three 

 joints are small, the fourth is distinct, but the fifth 

 and sixth run one into the other. 



The legs are long and very slender. Fig. 19 repre- 

 sents a foot : the pads are very small, but the hooks 

 are of moderate length; thus indicating that the fly 

 does not often walk on flat surfaces. 



The wings of Bombylii are long and powerful. 



The namesof theveins maybe learnt from fig. 4S; and 

 we would remark in passing, that as the Diptera 

 are in a great measure classified according to the 

 venation of their wings, it is always important to note 

 the characteristics of the wing of a strange species, 

 and to make a drawing of it. The spaces between 

 the veins are called areolets ; and the central one 



Fig. 49. Foot of B. major, x 45. 



Fig. 50. Mouth of Bombylius major, x 12: la, labium; Ibr, 

 labrum; I, lingua ; mx, maxillae; mp, maxillary palpi ; It, 

 lancet; t, opening tendons; V\ closing tendons;/, fulcrum. 



(d) named " discoidal," should always be particu- 

 larly noticed, because it varies considerably both in 

 shape and position, and a glance at it will often give 

 a clue to the family and genus of an unknown 

 insect. The secondary wings, or halteres, of humble- 

 bee flies are small, and hidden by the down which 

 clothes the body of the insect. 



We believe that in their larval and pupal stages 

 Bombylii are parasitic on bumble-bees, the parent 



