HARDWICKE'S SCIENCE- GOSSIP. 



171 



in support of my imagination : — " The assumption 

 that the Greensand is formed of the casts of Eora- 

 minifera should be rejected for the following 

 reasons: — 1st.. 2nd.. 3rd, and conclusive. The 

 grains of glauconite in the Irish Greensand, when 

 examined under the microscope, show no real 

 resemblance to Eoraminifera." 



Mr. Stewart now says that he never met with an 

 Irish naturalist who was capable of such an assump- 

 tion, but I am afraid his friends can hardly make 

 the same observation. Lastly, with regard to the 

 " authorities," my reference to which has inspired 

 more than half of Mr. Stewart's letter, 1 beg to 

 assure him that the word is not used by me in any 

 peculiar sense of my own, and I am at a loss to 

 understand why he should not suppose that I used 

 it in precisely the same sense as he did himself in 

 the paragraph I quoted at the end of my letter. I 

 did not intend the word to have any other signifi- 

 cation more or less than that which he there meant 

 it to convey, and I gladly take an opportunity to be 

 in accord with him, at any rate, on one point. This 

 affords us, moreover, a fitting occasion to close our 

 tilting. Mr. Stewart will see, with me, I think, that 

 there is little likelihood of our settling the questions 

 which beset the origin of greensands by any further 

 correspondence. 



Cambridge. A. J. Jukes Browne. 



NOTES ON THE DIPTERA. 



VI.— CoNOriDiE. 



T?VERY entomologist must be aware that the 

 •*-* two best-known families of the Diptera — the 

 Muscidez and the Syrphidae, are closely connected 

 one with the other ; but he is not so likely to know 

 that there are other families besides the Syrphidae, 

 whose resemblance to the Muscidae is so great that 

 it is difficult to decide whether or no they should 

 be reckoned as separate. Such are the Conopidae, 

 the subject of this paper. They are a group of flies 

 on the classification of which authorities cannot 

 agree ; since some would range certain genera under 

 the Muscidae, which others place with the Conopidae 

 proper. We shall include in the family the three 

 British genera Conops, Zodion, and Myopa, 

 following the arrangement of Professor Westwood, 

 although Walker, in his " Insecta Britannica," is 

 almost inclined to class the two latter with the 

 Muscidae. 



The three families, Syrphidae, Muscidae, and Cono- 

 pidae seem to be all linked together by a family of 

 small insects called Pipunculidce, which are so 

 much like each of them that they might almost be 

 classed with either. 



The Conopidae are not common insects, or at least 

 are not commonly seen ; but the entomologist in 

 search of other diptera is sure to meet with speci- 



mens now and then. They may, however, be 

 commoner than they seem to be, and the rarity of 

 their appearance may be due to their habits. At 

 any rate, they are widely distributed, for the very 

 same species may be found not only in all parts of 

 the British Isles, but also over the greater part of 

 Europe. Their life-history is peculiar, and not too 

 well understood. We ourselves have not been able 

 to trace it ; but we have gathered a little informa- 

 tion from various books treating of the Diptera. 

 All of them appear to be parasitic upon Hymeno- 

 ptera, for they are always found in places where bees 

 and wasps are abundaut. Conops quadrifasciata is 

 well known to be a parasite living within the bodies 

 of large humble-bees, since specimens have at times 

 been reared which have made their escape from the 

 abdomen of a bee after it has arrived at the imago 

 state. It is astonishing that a humble-bee can live 

 with so large an insect as a Conops within its body- 



Of the transformations of the other genera 

 hardly anything is known : Walker merely says that 

 "the species are probably parasites of other in- 

 sects." Will not some entomologist, living in the 

 country and having plenty of leisure, devote him- 

 self to tracing out the life-history of these curious 

 flies? It will probably prove as interesting as 

 that of the beetle Sitaris, related in Sir John 

 Lubbock's " Metamorphoses of Insects " as in- 

 vestigated by M. Fabre. (In relation to the larva 

 of this beetle, we would remark that this year we 

 have found it clinging to Bombylii, or humble-bee 

 flies. This is " circumstantial evidence" that Bom- 

 bylii frequent the nests of Anthophorae (a genus 

 of bees) to lay their eggs, since Sitaris itself, from 

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

 but only of a bee.) 



The three genera Conops, Zodion, and Myopa 

 are distinguished as follows : — The antennae of the 

 first genus, Conops, have no bristle ; i.e., the joints 

 which in its relatives are prolonged into a slender 

 filament, are quite short and thick ; they are situated 

 at the tip of the antennae, and not on the upper 

 surface (compare figs. 96 and 100), but the antennae 

 of the second and third genera, Zodion and Myopa, 

 are like the antennae of a muscid, save that the 

 bristle is shorter and thicker in proportion to the 

 other joints (see fig. 100). Myopa may be dis- 

 tinguished from Zodion by its mouth, which is 

 jointed, instead of being straight like the mouth of 

 a Conops (compare figs. 99 and 100). 



Conops. — The Greeks applied'the word "conops" 

 (Kwvwip) to biting flies of the Gnat kind, and there- 

 fore it is difficult to understand the reasons which 

 prompted the entomologist, who first gave it to this 

 genus ; perhaps he did it on the logical principle 

 of "lucus a non lucendo," since the Conopes are 

 but very distantly related to gnats, and do not bite 

 at all. Conopes only appear during the hottest part 

 of the warmest days of July and August. They 



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