158 



HARDVv'lCKE'S SCIENCE-GOSSIP. 



for the central one, though narrow where seen 

 between the two large pads, yet on the under-side 

 of the last joint of the tarsus, where it arises, is 

 broad and furnished with tenent hairs. Besides 

 these, there are tenent hairs on the under-sides of 

 the last two joints of the tarsus, which may be 



Fig. 93. Wing of D. rufipes, x 7 diams. For names of the veins see 

 flg. 87. Tt differs from the wing of asilus as follows : the radial vein, r, 

 does not join the sub-costal, sc, before entering the costal ; nor does 

 the externo-medial, em, join the front fork of the uost-brachial, po; nor 

 the bind fork of the post-brachial join the anal, an. 



called " auxiliary pads," and also a regular brush 

 of hairs, not tenent but ordinary, on the first joint. 

 Add to this the two stiff claws, as sharp as needles, 

 and numerous hairs and bristles all along the leg, 

 and a more effectual piece of mechanism for grasp- 

 ing, than the foot of an asilus, can hardly be con- 

 ceived. 



We now come to the genus Leptogaster (\sTrr6g, 

 slender, and yaoriip, belly) of which our only re- 

 presentative, L. cylindricus, is the commonest of 

 our native Asllidce. It is so named from the cylin- 

 drical shape of its abdomen, which is extremely 

 long and slender. Au idea of the strange appear- 

 ance of the fly may be obtained from fig. 89, which 

 shows 'it in the position that it usually assumes 

 when at rest. This fly is the very opposite to a 

 bombylius, or humble-bee fly, which is short and 

 broad, whereas the leptogaster is long and thin. 

 The former spends the greater part of its life on the 

 wing, but the latter scarcely ever flies ; and, as one 

 might expect, the wings of the one and the feet of 

 the other are greatly developed, so that the bom- 

 bylius has large wings and slender legs, and the 

 leptogaster has tiny wings and stout legs. A foot 

 is shown at fig. 91. The claws are unusually large, 

 and are set almost at right angles to the foot, so 

 that they nearly turn back underneath it. The two 

 outside pads are altogether absent, but the middle 

 pad although not broad is very strong — like a third 

 claw (e, fig. 89). The only substitutes for the ordi- 

 nary onychia are the auxiliary pads (p, fig. 89), 

 similar to those mentioned in the description of 

 the foot of asilus, but they are not so large, even 

 comparatively, as in that fly. This peculiar form 

 of feet, adapted, like those of the animal known as 

 "the sloth," for a climbing life, renders walking on 

 a flat surface almost an impossibility to a lepto- 

 gaster; in fact, the creature may be said to be "at 



sea" when it gets on the ground, where it is in a 

 worse plight than the proverbial " cat in walnut- 

 shells." 



The colouring of L. cylindricus is simple, but 

 pretty. Its integument is black, but is wholly 

 concealed by a very fine brownish gray pubescence. 

 The eyes are bronze green, the face 

 golden yellow, and clothed with long 

 yellow hairs. The legs are yellow, with 

 black markings. The antenna? and 

 mouth are minute: an outline of one of 

 the former is given at fig. 90 a. 



The size of the fly is very variable, it 

 being sometimes as much as § inch, and 

 sometimes as little as ■$ inch, in length. 

 Although it is such a slender insect, it is 

 by no means a weak one, its frame being 

 tough and muscular ; and, no doubt, it is 

 just as fierce as its brethren, so that any 

 unhappy little insect getting within reach 

 of its talons would have but a slight 

 chance of escape. The most likely places in which 

 to find leptogaster are barren spots overgrown with 

 thistles and coarse grass, where they may be often 

 found in hundreds. Specimens can generally be 

 obtained by sweeping with the net in ripe mowing- 

 grass. 



It is most probable that those who are not ac- 

 quainted with the Dioctrice, often pass them by as 

 ichneumon flies, for, in outline, colour, and manner 

 of flight, they have a certain resemblance to this 

 family of the hymenoptera. But, if one be caught 

 and examined, it will be seen that it is a dipterous 

 insect, which may at first be mistaken for another 

 species of Leptogaster. It will be found to differ, 

 however, from a leptogaster, in the form of the 

 antennse, feet, and other parts. Dioctrice are more 

 elegant in form than many of our other As'uidce, and 

 surpass most of them in beauty of colour. 



They live chiefly in hedges and low bushes, and 

 have a great liking for stinging-nettles : they are 

 also found in the same places as the previous genus. 

 Dioctria rufipes is a fly about -^ inch long and 

 about 1 inch across the expanded wings. The body 

 is black, the front of the head gold-coloured and 

 shining, and the eyes bronze green. The first and 

 second pair of legs are red, and the hinder pair 

 black. The wings are colourless or tinged with 

 broWn, with black veins, the halteres light yellow, 

 and very conspicuous. The antennse, as may be 

 seen in fig. 92, are much larger than those of the 

 other insects described in this paper, being almost 

 the largest antennae possessed by any of theBracky- 

 cera, or short-horned diptera, in the British Isles. 

 They are also of a different character, being hairy, 

 and having the olfactory capsules smaller. It seems 

 probable that they are used as feelers, for their 

 length, flexibility, and the possession of hairs, 

 would fit them for that purpose. 



