THE ENTOMOLOGIST. 



Vol. XXIL] AUGUST, 1889. [No. 315. 



NOTE UPON ATHERIX IBIS, Fabricius. 



By T. R. Billups, F.E.S. 



(Plate 7.) 



The very curious group of Diptera figured on plate 7, by 

 Mr. Frohawk, was found in the neighbourhood of Gondover, near 

 Shrewsbury, by Mrs. Close, of Gondover Hall, who sent the mass 

 of flies to the editor of the ' Field ' newspaper for identification.* 

 In due course they were handed to Mr. John T. Garrington, who, 

 finding some living Hymenoptera among them, kindly sent them 

 on to me for examination. 



This group was found attached to a sallow twig, which was 

 part of a bush overhanging a lake. It consists entirely of females 

 of Atherix ibis, one of the family Leptidge, which inhabit fields 

 and woods near water. A. ibis is a somewhat local insect, that 

 has been recorded from various localities in England and Scotland, 

 but is common in many places on the continent of Europe. 



When about to deposit her ova, the female A. ibis generally 

 selects the branch of a tree or bush overhanging water, preferably 

 a running stream. Upon this twig she deposits her eggs, and 

 then almost immediately dies. She is followed by others, which 

 conduct themselves in like manner, to the same spot, and so 

 form the pear-shaped mass (as illustrated), varying in size to 

 several inches long, and proportionately wide in diameter. These 

 females, which often number many hundreds, deposit their eggs 

 upon each other when the twig has become covered. The larvae 

 hatch from these ova, and fall into the water below to undergo 

 their metamorphoses therein. 



Curtis, in ' British Entomology,' where he figures both male 

 and female, says that the males may be found in numbers on the 

 banks of rivers after floods. 



I * [The block illustrating this plate has been kindly lent to the editor of the 

 ' Entomologist ' by the proprietors of the ' Field.'— J. T, C] 



ENTOM. — AUGUST, 1889. T 



