246 



HARDWICKE'S SCIENCE-GOSSIP. 



the grooved rod were cut square. The packet once 

 tightened, it requires only to be corded securely ; and 

 the press taken to pieces can be used for preparing 

 another set, so that for each company one press is 

 sufficient. Eventually, thanks to it, the parcels both 

 going and returning are sufficiently secure to prevent 

 the joltings on the road from loosening them, to the 

 great damage of your papers going, and especially to 

 your collections returning. 



E. de C. 



TEETH OF FLIES. 



By W. H. Harris, Cardiff. 



No. i$.—SCHCENOMYZA LITORELLA, Fall. 



ON the 30th of May, 18S6, the fly, whose dental 

 organs form the subject of the accompanying 

 sketch, was taken while walking in my garden. At 

 first sight, to all appearances, it was a very ordinary 

 creature indeed. It 

 was small, measuring 

 about three-tenths of 

 an inch in length, pro- 

 portionately slight, 

 and possessed no very 

 distinctive features to 

 attract attention. The 

 dissection of the 

 mouth-organs alone 

 revealed to me I had 

 made the acquaint- 

 ance of a stranger ; 

 accordingly I at once 

 despatched the crea- 

 ture to Mr. Meade, 

 who has so often 

 kindly assisted me in 

 identifying my cap- 

 tures. I soon had the 

 satisfaction to learn 

 from that gentleman 

 that, apart from the 

 peculiar form of teeth 

 it gave me, it also 

 furnished him with a 

 been as belonging to 



Fig. 133. — Teeth of Scluenomyza litorella, Fall. 



species he had never before 

 Great Britain. He had in- 

 cluded it in his annotated list of British Anthomyiidae, 

 on the authority of the late Mr. Haliday, who took it 

 on the sea-coast at Holywood in Ireland. It was 

 one of the little-known marine diptera he was anxious 

 to meet with, and hoped I should be able to take 

 some more specimens. 



With such an incentive, I was soon off on the search. 

 The coast is about two miles distant from my house ; 

 a strong easterly wind had been blowing. Taking 

 my cue from this, I wended my way to the Rumney 

 marshes, and in the course of the morning had the 

 satisfaction to capture several specimens of the species. 



The general characteristics of the schcenomyza, as 

 given in the list referred to above, are as follow, viz. : 

 " Eyes bare, remote in both sexes ; antennae sub-erect, 

 approximate at their bases, and divergent at their 

 extremities, having the third joint dilated ; arista 

 bare, abdomen neither thickened, nor dilated at its 

 extremity ; scales of alulets very small and equal ; 

 wings with the internal transverse veins placed beyond 

 the termination of the second branch of the first 

 longitudinal veins, anal veins very short." 



The mouth-organs in this creature are arranged on 

 a plan similar to that of Caricea tigrina, Science- 

 Gossip, 1885, p. 205. The lobes of the proboscis, 

 however, are slightly more flexible. There are three 

 main teeth in each lobe, flanked by two smaller 

 ones, one on either side. All these teeth are 

 provided with a couple of denticles remarkably 

 well developed ; the upper portions of the teeth are 

 very dark in colour, hard and brittle ; the basal 

 portions light amber and more flexible. 



Besides the teeth 

 there are four patches 

 of chitinous plates, 

 which have been 

 compared in the case 

 of C. tigrina to gastric 

 teeth. The groups 

 occupying the fore 

 part of the mouth 

 consist of moderately 

 stout plates, and are 

 largely developed, 

 while those situate on 

 the posterior portion 

 are much smaller and 

 the individual plates 

 much finer. A sickle- 

 shaped organ (not 

 figured) composed of 

 very dark and hard 

 chitine is also present ; 

 its free movement 

 backwards and for- 

 wards against the 

 teeth commences the 

 crushing of the creature's food, and the four groups 

 of hair-like plates continue the process until it is in 

 condition to be conveyed to the stomach. 



In the accompanying illustration one lobe only of 

 the proboscis is shown. On comparing it with 

 Caricea tigrina it will be noted the basal portions of 

 the teeth are more separated in the present example ; 

 that there is not so much disproportion in the size of 

 the main members of the group ; that, allowing 

 for the difference of magnification, it is little more 

 than half the size, and therefore represents a very 

 formidable set of organs. 



