236 LEPTIDiE 



Lampromyia sericea from South Africa, in which species the elongate 

 third joint of the antennae shows traces of annulations ; in the Vermilco- 

 ninm also the arrangement of the tibial spurs seems to he variable. After 

 clearing off these three subfamilies the Leptinm and Cho-ysopilince are 

 distinguished by the two spurs on the hind tibiae of the former and the 

 one spur of the latter, and although this character may appear to be 

 trivial it is constant (although the spurs are stunted in Hilarimorpha). 



Synonymy. — As the name Leptis is obviously derived from XeTrros (thin) I cannot 

 understand the possibility of any family name excejit Leptidce. Would those 

 persons who advocate Leptididce also use Canididce or Felididcs because Canis and 

 Felis end in " is ".? Empididoe is comprehensible because there is a word ^/xttis with 

 a genitive efj-iridos, but even that emendation is unnecessary and undesirable. 



The following is a translation of a short paper by Mik in the Wiener 

 entomologische Zeitung, XVIII., 230, on the characteristic " touch-hairs " 

 which exist on the tarsi of some Diptera : — 



" Upon a hitherto unconsidered Organ of Touch in Diptera, 

 " especially in certain Leptidce and Talcmidce. 



" Everybody who has noticed the life habits of Diptera when collecting them 

 " will have been struck by the peculiar behaviour of some of the small Empidaj, 

 " Dolichopodidse, etc. on the leaves of plants. More particularly the species of 

 " Tachydromia (Platypalpus), and in the Dolichopodidtje the species of Psilopus, and 

 " Ilypophyllus, Agramyzidie, Sciara, Fsychoda, and others, while running about on 

 " leaves at times lower their heads and press the mouth down on the surface of the 

 " leaves, after which they lift up their heads as if they had been drinking. Many 

 " Diptera are known to be carnivorous. Not impossibly they obtain through these 

 " movements the debris of other insects or very small mites, but not improbably 

 " they nibble drops of sugar from Aphides or suck up moisture, particularly such 

 '' species as specially drink nectar, 



" The behaviour of the species of the genus Leptis is remarkable, as they also 

 " apparently drink from leaves while making similar movements of the head to 

 " those mentioned before, though at the same time they make another movement 

 '' with the front tarsi. Whilst using the posterior legs to rest upon, or move Avith 

 " slow steps on the surface of the leaves, they make curved movements with both 

 " front tarsi as if brushing or mowing off the upper side of the leaves, they rest the 

 " end of the tibiae on the leaf and move the whole tarsus backwards and forwards 

 " in a curve on the upper side of the leaf, and at the same time the front tarsi 

 " tremble in a peculiar way, and these movements continue both when the fly is 

 " resting or moving. They are at rest only when the fly lowers its head on to the 

 " leaf and presses its proboscis to it, as stated of the other Diptera. This apparent 

 " drinking occurs with Lepttis only when both front feet have come nearest to each 

 " other in the mowing movement, so that they can nearly touch the head on both 

 " sides. Involuntarily the idea is aroused that the fly holds what it has l)rushed up 

 '' l)etween the front feet so that it can more easily take it up with the proboscis. 

 " However I have not noticed with the naked eye any strange corpuscles on the 

 " surface of the leaves. 



" But the movements of the whole insect show that it is seeking and feeling or 

 " groping about, and raise the question as to whether this apparent clearing away 

 " on the upper surface of the leaf with its front tarsi is not really a ' touch ' move- 

 " ment, and whether something cannot be gathered from the formation of the tarsi 

 " which would indicate a ' touch ' organ. 



"In fact I believe I have found this organ, and consequently I interpret this 

 "sweeping trembling movement of the front tarsi as a sense of 'touch.' 



" I made my first observations on a male of Leptis scolopacea L. and subsequent 

 " ones on a female of L. immaculata ]\Ieig. 



" The usual clothing of the tarsi of the species of Leptis is composed of shorter 



